Thank you sincerely for reporting this! I've been walking back and forth to the Gym for half an hour now and can't replicate it (to quote the npc, "This walk never gets old!" :( ). I'm guessing something triggered in your save that's not in mine. If you don't mind, would you grab your save file named Game.rxdata in C:\Users\(YourUSERNAME)\AppData\Roaming\NOT Pokémon
and then upload it to https://ufile.io and post the link for me? That would help a great deal!