Transferring back to an old realm with my previous name that is now available again

if you were on Server X with Name Y over 6 months ago and now on Server A with Name B, if you want to transfer back to Server X with Name Y but it now shows as “Last login: Never, Last update: Never” on WCL and Name Y is now available on Server X, if I go back to Server X, will that cause issues with log merging?

Should merge just fine as long as when you look at your list of characters in Settings you see “Enabled” for the Auto log merge stuff.