Week mode not rendering correctly

I'm currently seeing an extra week at the end of the month, kind of like:

I would expect this behavior if I have the week mode set to "fixed" (since that would set it to show exactly 6 weeks), however it's currently set to "liquid". I get the same issue if I use "variable". And oddly enough, the number of weeks do indeed very month to month:

• 6 in April: Incorrect (too long)
• 6 in May: Correct
• 5 in June: Correct
• 5 in July: Correct
• 5 in August: Incorrect (too short)
• 5 in November: Incorrect (too short)

Any ideas? I'd be happy to actively debug / try new things if anyone has a suggestion.