application logging in some apps does not work

Hi,  we have RTF on premises, running on AWS with EKS (kubernetes service). So far all is good but as due to Platinum license we have to have own logging and we use SPLUNK which also is on premises.  As instrumentation service, we use the signalfx/splunk-otel-collector-chart. So far also all good but, since later updates of the RTF - I do not remember exactly when, I'd say maybe from 2.5.. we have problems.  Some apps do forward app logs and some don't.  I do not see any pattern. Maybe someone knows the problem and a way to solve it?