When episodes are moved on TVDB the episodes and associated plays are not moved
As an example I watched a bunch of The Adventures of Sonic the Hedgehog episodes in 2015. Back then the episodes were split into 4 seasons, However since the all the episodes have with exception of the Christmas special have been moved into a single season. (see https://forums.thetvdb.com/viewtopic.php?t=57933)
However, instead of the episodes being moved into season 1, they have been duplicated into season 1, so there are now multiple copies across the seasons (eg "Blackbot the Pirate" is now 3 episodes in two seasons - all with the same TVDB link)
Since TVDB episodes all have an ID it should be possible to check if the ID already exists for the series being refreshed and if so, move the episode rather than make new copies.