How to fix the fake 'Gym is under attack' notification glitch in Pokemon GO

It's the summer, and with it came a new grand Pokemon GO update that turned gym battles on their heads, and introduced Raid monsters to salivate over and earn copious amounts of XP points from. By now, however, you might have run across one of the inevitable glitches that occur after each major game overhaul on such a grand scale. Oftentimes, after you've interacted with a gym by either battling it, swiping for items, or simply trying to put your creature in a friendly one with available slots, you are unable to do so.

While the first player is able to place their critter in ...