font changes when I copy/paste in notes on iphone

You see these options when you're modifying text that's saved on your iCloud.

If the note was created e.g. as part of your Gmail account - this is when the font substitution happens.

I have a few notes on my Gmail account and when I do a cut and paste on a particular note I the pasted note changes from the typical arial looking font to a times new roman looking font.

These font changes also happen when you delete spaces on existing text, which is very annoying since you've got a note that has multiple fonts and sizes...

What does the font look like? You can change it by selecting the text, then pressing the 'Aa' icon above the keyboard, as shown-

You can then change the formatting by selecting a different option-

That's certainly odd. The formatting bar should be there regardless.

Perhaps try deleting and reinstalling the Notes app? You'll have to back them up, of course.

You're welcome- good luck.