Content-Type-Groups available at $contentType->getContentTypeGroups() is possibly incomplete when ezpublish.spi.persistence.cache.inmemory.enable is set to true.

Steps to reproduce:

• Enabled in-memory-cache
• In new context (fresh run without established in-memory-cache)
• Load a content-type-group with content-type-service
• Load type list by content-type-group with content-type-service
• Check list of groups (of type with multiple groups) returned by getContentTypeGroups -> incomplete (same in <2.5 releases)
• Load this content type by ID -> incomplete (had the full list in <2.5 releases)

This behaviour is only reproduceable when in-memory-cache is enabled.
When in-memory-cache is disabled -> the last step will result in the object containing all groups as expected (as in sub 2.5 releases).