Has Sony crippled DLNA?

Both of my BDP-S3100 players were doing just fine with my ripped DVDs and Blu-Rays. Most are in MKV containers, but some BDs are M2TS. The Sony plays these without transcoding.
About a couple of weeks ago, I have suddenly had issues with BD rips, regardless of container. It doesn't matter if I use MakeMKV (MKV) or MovieRescuer (M2TS). Sometimes the Sony shows them in the correct container (the video list shows container type, or if transcoded, the transcode container), some will show MPEG instead of the actual container, and some won't be listed at all. If I open Media Browser, the video is listed there (and will play), so it's not a Serviio issue. If I use my Roku or Panasonic, the video appears and will play (of course, both require transcoding). Finally, even many videos that have worked fine suddenly hit around 15 minutes or so and freeze. The player hasn't frozen, and I can hit stop and the play to resume the movie at the same place. However, once the freeze happens, it now repeats itself every 5 minutes or less. Makes the movie pretty much unwatchable.
I haven't to my knowledge updated the firmware that recently, but I'm wondering if they had something embedded that started recognizing ripped videos and is kicking in some sort of blocker. So far, it has only affected my BD rips. DVD rips are playing fine. Can older firmware be installed, or does Sony block firmware versions older than what is installed?
Anyone else encountering issues playing back movies without interruption? I am seriously considering replacing the Sony players with another brand, if anyone has suggestions about playing the files without transcoding.
About a couple of weeks ago, I have suddenly had issues with BD rips, regardless of container. It doesn't matter if I use MakeMKV (MKV) or MovieRescuer (M2TS). Sometimes the Sony shows them in the correct container (the video list shows container type, or if transcoded, the transcode container), some will show MPEG instead of the actual container, and some won't be listed at all. If I open Media Browser, the video is listed there (and will play), so it's not a Serviio issue. If I use my Roku or Panasonic, the video appears and will play (of course, both require transcoding). Finally, even many videos that have worked fine suddenly hit around 15 minutes or so and freeze. The player hasn't frozen, and I can hit stop and the play to resume the movie at the same place. However, once the freeze happens, it now repeats itself every 5 minutes or less. Makes the movie pretty much unwatchable.
I haven't to my knowledge updated the firmware that recently, but I'm wondering if they had something embedded that started recognizing ripped videos and is kicking in some sort of blocker. So far, it has only affected my BD rips. DVD rips are playing fine. Can older firmware be installed, or does Sony block firmware versions older than what is installed?
Anyone else encountering issues playing back movies without interruption? I am seriously considering replacing the Sony players with another brand, if anyone has suggestions about playing the files without transcoding.