Yeah, it's not a drama.

The reason that the body doesn't alarm as much to Pseudouridine, is that it's not a 'natural' RNA base. Meaning that, for the most part, nature really never uses it and so we haven't evolved to look out for it. Nature uses Uridine and so immune systems have evolved to look out for random bits of RNA in the body that use it and then clean that all up.

It's like if you're looking to clean up legos in you house with a romba that only cleans up legos. And all of a sudden it finds a duplo. It's going to take a hot second to figure out what to do with the duplo. And in that time, you can sneak by and build a duplo fort. (Look, I know this analogy is bad, but it's the best I can come up with on the fly, sorry. If anyone else wnats to come up with a better one, please do!).

The Pseudouridine is used up and degraded very quickly inside the cell, minutes at the very very longest, more like microseconds. It's just part of a messenger (the 'm' in 'mRNA') to tell the cell to do things.

You might see mRNA gene editing in factory farms, but it would just be easier to do germline editing instead and skip spraying animals, plants, and fungi. Why waste the equipment, right?