Delete session after error Internal error [Error/Core]

Dear Experts,

Can someone help me with this strange issue ?

The users are automaticaly kicked from the program. I can saw from SM21 that they use program SAPMHTTP.

The only thing that I can find in the logs is this error, but the more strange thing is that it didn's appear every time. Some times there is nothing in the logs. Is there someone who face this error before and can you please provede me solution for it ?

ThPerformDeleteThisSession: switch off statistics

*** WARNING => ThResFreeSession: free resources of T19_U19888_K0 (normal mode, complete free), rc=ERROR-CORE-INTERNAL_ERROR, db_action=TH_DB_ROLLBACK [thxxmode.c 890]

{root-id=1402EC83F8681EDC9CF17DACDB545B1D}_{conn-id=1402EC83F8681EDC9CF17DACDB547B1D}_1

***LOG R47=> ThResFreeSession, delete () [thxxmode.c 1166]

ThResFreeSession: delete T19_U19888_K0