the backend is removing and adding channels or is changing channel uid's. that's the backend's or the add-on's problem and xbmc is behaving as intended. contact the add-on author(s) if it's not working properly with vnsi.
This must be a change to the VNSI addon then because for me this issue has only appeared with this version of XBMC-PVR
reset the epg database in the gui settings. if it's still failing after a reset, then post a debug log please.
Reset the EPG - http://pastebin.com/utupRcWJ
Made no difference.
Resetting the PVR database makes no difference.
Deleting the TV and EPG .db files makes no difference either.