Cohort size retrieval not working in all menus

[franzplri]

There are different places where you can retrieve a cohort size using the interface - what I tested:

1. Projects -> Create Project - Define Cohort -> Determine Button (ok)
2. While defining a query in the "Criteria Editor" (ok)
3. Search -> Determine Button (what users will generally use - not working)

Using the same search query/criteria the cohort size is correctly displayed in 1 and 2 (398 in this case).
1:

2:

while it does not work in 3.

The Firefox developer console is showing a statuscode 500:

Curiously, the number is displayed correctly again as soon as you click on "next step" and switch to the "data filter" tab:

As openEHR repository we are using the better platform not ehrbase. But since the query works, just not in all places, I think the bug is related to the implementation of the portal.