Google Optimize A / B tests freeze the home page

I'm trying to run 4 A / B tests with the help of Google Optimize, on the same domain. The test must be excluded by targeting. However, in most cases, when I access the home page (see: test 1a, 1b below), the page freezes. The test configuration follows.

Variants for all tests:

+ --------------------- + ------------------------- +
| Original | Option A |
+ --------------------- + ------------------------- +
| https://example.com | https://example.com?v=b |
+ --------------------- + ------------------------- +

Configuration for each test:

Test 1a (English, home page)

+ --------------------- + --------------------------- --------- +
| Should run on | Targeting |
+ --------------------- + --------------------------- --------- +
| https://example.com | * URL matches: https://example.com |
+ --------------------- + --------------------------- --------- +

Test 1b (German, homepage)

+ ------------------------ + ------------------------ --------------- +
| Should run on | Targeting |
+ ------------------------ + ------------------------ --------------- +
| https://example.com/de | * URL matches: https://example.com/de |
+ ------------------------ + ------------------------ --------------- +

Test 2 (EN + DE, document page) – excludes tests 1a and 1b

+ ------------------------------------------ + ------ -------------------------------------------------- ---------------------- +
| Should run on | Targeting |
+ ------------------------------------------ + ------ -------------------------------------------------- ---------------------- +
| https://example.com/courses/viewfile/123 | * The URL contains: https://example.com |
| https://example.com/kurse/vorschau/123 | * The URL contains one of the following: viewfile, vorschau |
| | * The path starts with: / course, / kurse |
| | * The URL does not end with any of the following: https://example.com, https://example.com/de |
+ ------------------------------------------ + ------ -------------------------------------------------- ---------------------- +

Test 3 (EN + DE, course page, university page) – excludes tests 1a, 1b and 2

+ ------------------------------------------ + ------ -------------------------------------------------- ---------------------- +
| Should run on | Targeting |
+ ------------------------------------------ + ------ -------------------------------------------------- ---------------------- +
| https://example.com/courses/789 | * The URL contains: https://example.com |
| https://example.com/kurse/789 | * The URL does not contain any of the following: viewfile, vorschau |
| https://example.com/universities/456 | * The path begins with: / courses, / kurse, / universities, / united |
| https://example.com/unis/456 | * The URL does not end with any of the following: https://example.com, https://example.com/de |
+ ------------------------------------------ + ------ -------------------------------------------------- ---------------------- +

The other URLs are accessible without problems, but it seems that the test configuration "kills" my homepage.

Ideas?