I believe I have figured out the issue because I have experienced the same thing. Whenever this happens, I look in my contacts and search for the word or name that was capitalized, even if it's just the first letter of the word, when it shouldn't be.
in other words, if I mention LISA in a dictation for a text and it capitalizes it, sure enough, if I go to my contacts and search for Lísa, one of several possible Lisa's whom I know is fully capitalized. The strange thing is that if I know five Lisa's, and there's only one that's spelled in all caps, it always picks the one in all caps. So much for doing things based on statistics.
I think you'll find that JERRY is spelled in all caps in your contacts, even if it's only one of several spelled in all caps. It's a very frustrating feature, at least in my mind. I have not talked to Apple about how to turn that off, if even possible.
We have a glen behind our building here in New York City, and whenever I refer to the glen in a text, it spells it with a G. Not that big a deal, but it's annoying. Every time I see a name or word spelled in all caps, I go to my contacts and fix it because I never intended to put it in that way. I suppose I wouldn't change my friend's name from Glen to glen just to accommodate a capital letter when I'm referring to the glen behind my building
I believe when I got my first iPhone and transferred my contacts from other software, many of them were capitalized because they were entered that way automatically when I received an email from someone who spelled their email address snd contact info in all caps.