Nulls or 0 received from SMA SunnyHomeManager in 15min inverval

Dear Community,
I managed to receive data from my SunnyHomeManager2, binding it as a SMA energy meter.
All values seem to be live and plausible, but on a almost regular bases of 15 minutes “0” (or perhaps “NULL”!?) is written in the database for almost all channels at the same time. Those being false is becomes apparently obvios at incemential values:

anybody with similar experience
maybe an idea why this happens (only SHM-values are effected)
and maybe a mitigation solution?

Thanks in advance!