'The Masked Singer' Sees Cursed Trailer with Toilet Flushing Issues

The 'Masked Singer' might have a cursed trailer on their lot ... because one of the mobile celeb dressing rooms has a toilet that just won't seem to flush.

Here's the deal ... each contestant hangs out in their own StarWagon trailer during long days on set -- not unusual for Hollywood productions -- but one of the trailers is having serious issues with plumbing.

Our 'Masked Singer' sources tell us one of the contestant's trailers had a clogged toilet, and the celeb had their entourage make the embarrassing call to alert production. It's kinda the whole point of "having people."

Anyways, the crew unclogged the toilet -- we've all been there -- but a few days later, we're told the same trailer had another clog, and the celeb again got their person to call on the plunger posse, much to the celeb's chagrin.

For context, these StarWagon trailers are equipped with bathrooms roughly the size of an airplane lavatory. Hey, it's still better than a porta potty.