Why did you set up custom expressions, rather than using the already existing ones? (Not criticizing, just asking.) When I enter a dynamic from the Expressions window, they go in correctly. I have F27.1, so I'm updating to 27.2, and I'll see how that works.
A few minutes later: F27.2 installed. Standard expressions work fine.
One thing I note: If you look at the standard dynamics (select one, click edit) they show the font as Music font (Finale Maestro 24 plain) But your custom expressions just show Finale Maestro. I don't know why. But the only fix I can think of is to simply use the existing expressions, unless they don't do what you want. And even if you need to change something, I would do it by editing an existing one.
I can’t think of a way, but that doesn’t mean there is‘t one. Unless you have hundreds of them, I would just delete and re-enter them. Many of the stock expressions have metatools, so re-entering them should go pretty quickly.