Formatting when "bold" not applied newly created cards of same note type, still works for older cards

I’m having this wierd bug that I don’t understand. I have a note type called “Projekt I am Boss (Einfach)” which has this style:

b { color: MediumSeaGreen !important; } /* BOLD STYLE */
u { text-decoration: none ; color: #FAB763; } /* UNDERLINE STYLE */  
i  { font-style: normal; color: #5EB3B3; } /* ITALICS STYLE */
a { color: LightGray !important; text-decoration: none; font-size: 10px; font-style: normal; } /* LINK STYLE */

Since upating to 2.1.50 (at least I think that’s it) the conditional formatting for bold no longer works for newly created cards, but still works fine created for cards before the update (or before the 07/05/22). It also still works for another card type (cloze deletion).

Example: This card has been created on the 07/05 and the conditional formatting works fine:

This card has of exactly the same note type has been created one day later and the conditional formatting for bold is broken. Conditional formatting for underlined still works though.

Disabling all addons didn’t fix the issue. Does anybody know what’s going on?

You may wish to update to 2.1.51: Changes in 2.1.50 to 59 - Changes