iPad streaming halts...

I’m running PMS on Synology NAS. There are multiple clients (3 Mac Book Pro, 3 Apple TV 4 gen, 2 iPad Air 2’s). All clients are connected via the same Wifi. All the content is encoded with H264 codec, no re-encoding required, always a direct play. Streaming to Mac Book Pros and Apple TVs always flawless. However iPads halt playing after about 5 minutes into the show/movie. Not a buffering issue as “three dots” never appear. It just stops and never recovers. If play button is clicked (touched), streaming resumes for a few seconds and stops again. Even 480p content. I’ve been watching NAS stats when it happens - plenty of RAM and CPU cycles available. PMS reports direct play on a single connected client with only 1.5 Mbps bandwidth. So I do not believe it is a network or NAS performance issue, but some quirk with iPad Plex Player. Please advise,

Thanks,
Glenn