Sorry if I used the wrong wording. I'm not a native English speaker, so I probably got it wrong. What I wanted to say by using the term "bogus" is that the error message seems to be wrong since there is no user noticable problem.
Reproducing is trivial, as I just need to play a recording. Nothing special. And the log file is *huge* since kodi is reporting the error several times per second.
Anyway, meanwhile I'm starting to understand what's going on: The vdr server is running LE 8.2.3, so the vdr server is still at protocol 10 while the client is already at 12. But the method GetStreamTimes was introduced only with protocol 11, so trying to use this is expected to fail. I'm amazed how well this all is working nevertheless (so far I did not notice any other problem). I'm now using a modified version of the client to prevent my disk being filled with kodi logs. I cannot yet update the server.
Please accept my apologies for the noise. At least I learned something new and the sound driver for this specific device will get a new module parameter in the kernel, as I was investigating this issue with one of the ALSA developers and we found out that it worked with older kernels only by luck (just choosing another device is not enough as this will lead to broken volume control; the new parameter will allow to get the same behaviour as with kernel 4.11.12).