Object of class Drupal\Core\Render\Markup could not be converted to int

I am trying to generate a simple line chart from a series of nodes which have a number(float) field and a value without any fractional part (basically, the field is populated with an integer in each of the four nodes), but I would like to leave the option of having up to two positions on the decimal in the future. There are four fields populated with a number. The fields in views are unformatted. I have tried with aggregation on and off.

The chart will not display and I get the following error in the error logs.

Notice: Object of class Drupal\Core\Render\Markup could not be converted to int in Drupal\visualization\Plugin\visualization\handler\HighchartsHandler->render() (line 90 of /var/www/root-of-site/modules/visualization/src/Plugin/visualization/handler/HighchartsHandler.php

Can anyone tell me what I am doing wrong?

Thank you.