Wrong aspect ratio for interlaced HEVC is a known issue at this moment, not related to that LAV error
Progressive HEVC in SD/HD is OK.
This is a little bit complex issue, related on to how interlaced video is encoded and broadcasted in H.265. User VictorLS has made some great workaround based on ffmpeg codec for SmartDVB (which has the same issue with LAV), but not sure if this would work for also for AltDVB, never tested that. Details are in HEVC_quasi_interlaced folder in latest SmartDVB archive. But personally do not recommend that, because it seems that this might also impact negatively on quality of SD/HD progressive and 4K/8K content.
Also I didn't try to set Video Aspect Ratio to eg Stretch 16:9 or something else in AltDVB (right mouse buton click on video), might be interesting to try
I'm hoping that @altxro will find some wise solution for this in future
LAV error: might be related to mixed two different LAV versions in AltDVB settings - internal and external with two graphics cards at one machine with different HW acceleration settings. Traces of this issue are visible on the net (author of KCP app player had ran into this issue back in 2015, info hidden behind spoiler
), it's hard to reproduce (specific PC configuration is needed) so LAV author didn't fixed that yet. Hope that you won't see it again