The report is over 2 threads so let me consolidate and add more here:
There was no issue on rc1 and previous releases. I have supplied diags from rc1 and rc3
Corelelec was set to SMB min 2 max 3, I changed that to min1 max 3 but no change. I don't know how to change the setting on an Android phone
WS-Discovery on Unraid was enabled, I disabled, no change
Netboid was enabled on unraid, I disabled, no change
AFP Legacy was enabledon unraid, i disabled, no change.
I have, reverting back to rc1 solves the problem for me. If you're expecting me to work out what's changed between rc1 and rc3 that's created this issue then I'm out of my depth. Happy enough to try different things when asked to help identify the issue, but I've reached my technical limitations.