Ajax parse error when updating colorbox settings in entity display options

This may not be a Colorbox specific issue, but it is observed when selecting Colorbox as the formatter in the entity display options.

When the "update" button is pressed to commit the new settings, an ajax error occurs:

An AJAX HTTP error occurred.
HTTP Result Code: 200
Debugging information follows.
Path: /system/ajax
StatusText: parsererror
ResponseText: 
Warning:  Unknown: Input variables exceeded 1000. To increase the limit change max_input_vars in php.ini. in Unknown on line 0
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id=\u0022field-display-overview-wrapper\u0022\u003E\u003Ctable class=\u0022field-ui-overview sticky-enabled\u0022 id=\u0022field-display-overview\u0022\u003E\n \u003Cthead\u003E\u003Ctr\u003E\u003Cth\u003EField\u003C\/th\u003E\u003Cth\u003EWeight\u003C\/th\u003E\u003Cth\u003EParent\u003C\/th\u003E\u003Cth\u003ELabel\u003C\/th\u003E\u003Cth colspan=\u00223\u0022\u003EFormat\u003C\/th\u003E \u003C\/tr\u003E\u003C\/thead\u003E\n\u003Ctbody\u003E\n \u003Ctr class=\u0022region-message region-visible-message region-populated\u0022 no_striping=\u00221\u0022\u003E\u003Ctd colspan=\u00227\u0022\u003ENo field is displayed.\u003C\/td\u003E \u003C\/tr\u003E\n \u003Ctr class=\u0022draggable tabledrag-leaf odd\u0022 id=\u0022field-artist-image\u0022\u003E\u003Ctd\u003EArtist Image\u003C\/td\u003E\u003Ctd\u003E\u003Cdiv class=\u0022form-item form-type-textfield form-item-fields-field-artist-image-weight\u0022\u003E\n  \u003Clabel class=\u0022element-invisible\u0022 for=\u0022edit-fields-field-artist-image-weight--3\u0022\u003EWeight for Artist Image \u003C\/label\u003E\n \u003Cinput class=\u0022field-weight form-text\u0022 type=\u0022text\u0022 id=\u0022edit-fields-field-artist-image-weight--3\u0022 name=\u0022fields[field_artist_image][weight]\u0022 value=\u00220\u0022 size=\u00223\u0022 maxlength=\u0022128\u0022 \/\u003E\n\u003C\/div\u003E\n\u003C\/td\u003E\u003Ctd\u003E\u003Cdiv class=\u0022form-item form-type-select form-item-fields-field-artist-image-parent\u0022\u003E\n  \u003Clabel class=\u0022element-invisible\u0022 for=\u0022edit-fields-field-artist-image-parent--3\u0022\u003ELabel display for Artist Image \u003C\/label\u003E\n \u003Cselect class=\u0022field-parent form-select\u0022 id=\u0022edit-fields-field-artist-image-parent--3\u0022 name=\u0022fields[field_artist_image][parent]\u0022\u003E\u003Coption value=\u0022\u0022 selected=\u0022selected\u0022\u003E- None 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selected=\u0022selected\u0022\u003E\u0026lt;Hidden\u0026gt;\u003C\/option\u003E\u003C\/select\u003E\n\u003C\/div\u003E\n\u003C\/td\u003E\u003Ctd\u003E\u003Cdiv class=\u0022ajax-new-content\u0022\u003E\u003Cdiv class=\u0022form-item form-type-select form-item-fields-field-artist-image-type\u0022\u003E\n  \u003Clabel class=\u0022element-invisible\u0022 for=\u0022edit-fields-field-artist-image-type--3\u0022\u003EFormatter for Artist Image \u003C\/label\u003E\n \u003Cselect class=\u0022field-formatter-type form-select\u0022 id=\u0022edit-fields-field-artist-image-type--3\u0022 name=\u0022fields[field_artist_image][type]\u0022\u003E\u003Coption value=\u0022colorbox\u0022 selected=\u0022selected\u0022\u003EColorbox\u003C\/option\u003E\u003Coption value=\u0022file_rendered\u0022\u003ERendered file\u003C\/option\u003E\u003Coption value=\u0022image\u0022\u003EImage\u003C\/option\u003E\u003Coption value=\u0022hidden\u0022\u003E\u0026lt;Hidden\u0026gt;\u003C\/option\u003E\u003C\/select\u003E\n\u003C\/div\u003E\n\u003C\/div\u003E\u003C\/td\u003E\u003Ctd class=\u0022field-formatter-summary-cell\u0022\u003E\u003Cdiv class=\u0022ajax-new-content\u0022\u003E\u003Cdiv class=\u0022field-formatter-summary\u0022\u003EContent image style: medium\u003Cbr \/\u003EColorbox image style: large\u003Cbr \/\u003EColorbox gallery type: Per page gallery\u003Cbr \/\u003EColorbox caption: Automatic\u003C\/div\u003E\u003C\/div\u003E\u003C\/td\u003E\u003Ctd\u003E\u003Cdiv class=\u0022ajax-new-content\u0022\u003E\u003Cdiv class=\u0022field-formatter-settings-edit-wrapper\u0022\u003E\u003Cinput class=\u0022field-formatter-settings-edit form-submit\u0022 alt=\u0022Edit\u0022 type=\u0022image\u0022 id=\u0022edit-fields-field-artist-image-settings-edit\u0022 name=\u0022field_artist_image_formatter_settings_edit\u0022 src=\u0022http:\/\/salsaspring.localhost\/misc\/configure.png\u0022 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for=\u0022edit-fields-field-artist-origin-parent\u0022\u003ELabel display for Artist Origin \u003C\/label\u003E\n \u003Cselect class=\u0022field-parent form-select\u0022 id=\u0022edit-fields-field-artist-origin-parent\u0022 name=\u0022fields[field_artist_origin][parent]\u0022\u003E\u003Coption value=\u0022\u0022 selected=\u0022selected\u0022\u003E- None -\u003C\/option\u003E\u003C\/select\u003E\n\u003C\/div\u003E\n\u003Cinput class=\u0022field-name\u0022 type=\u0022hidden\u0022 name=\u0022fields[field_artist_origin][parent_wrapper][hidden_name]\u0022 value=\u0022field_artist_origin\u0022 \/\u003E\n\u003C\/td\u003E\u003Ctd\u003E\u003Cdiv class=\u0022form-item form-type-select form-item-fields-field-artist-origin-label\u0022\u003E\n  \u003Clabel class=\u0022element-invisible\u0022 for=\u0022edit-fields-field-artist-origin-label\u0022\u003ELabel display for Artist Origin \u003C\/label\u003E\n \u003Cselect id=\u0022edit-fields-field-artist-origin-label\u0022 name=\u0022fields[field_artist_origin][label]\u0022 class=\u0022form-select\u0022\u003E\u003Coption value=\u0022above\u0022\u003EAbove\u003C\/option\u003E\u003Coption value=\u0022inline\u0022\u003EInline\u003C\/option\u003E\u003Coption value=\u0022hidden\u0022 selected=\u0022selected\u0022\u003E\u0026lt;Hidden\u0026gt;\u003C\/option\u003E\u003C\/select\u003E\n\u003C\/div\u003E\n\u003C\/td\u003E\u003Ctd\u003E\u003Cdiv class=\u0022form-item form-type-select form-item-fields-field-artist-origin-type\u0022\u003E\n  \u003Clabel class=\u0022element-invisible\u0022 for=\u0022edit-fields-field-artist-origin-type\u0022\u003EFormatter for Artist Origin \u003C\/label\u003E\n \u003Cselect class=\u0022field-formatter-type form-se

One can still commit their settings when pressing the save button at the bottom of the page.