I tried to your steps and it did not crash for me. I have all expansion DLCs except Way of Life and Sunset Invasion.
I loaded your savegame.
I clicked on your ruler's portrait in the upper left corner. Result: Character detail window appears.
I clicked on the marriage rings. Result: Marriage prospects list appears.
I clicked on the ruler's portrat in the upper left corner again. Result: Marriage prospects list closes.
No Crash.
I think you clicked on the marriage rings twice because there is a bug that will crash the game if you try to open the marriage prospects list while it is already open.
I load your savegame.
I click on your ruler's portrait in the upper left corner. Result: Character detail window appears.
I click on the marriage rings. Result: Marriage prospects list appears.
I click on the marriage rings again. Result: Nothing appears to happen. <-- ADDED STEP
I click on the ruler's portrat in the upper left corner again. Result: Crash.
R6025 pure function call error.
After you click the marriage rings while the marriage prospects list is already open you have sealed the deal and the game will crash. There are a lot of different ways that crash can occur at that point. You can close the marriage prospects window that is open then hover your mouse anywhere over the character detail window. You can close the marriage prospects window then press escape. You can open the dynasty tree and click on the portrait of any person in it. You can just click the portrait in the upper left corner.
There is a similar crash with the title claimants window if you open it while it is already open. I reported both of these in version 2.3.3 and they were already known issues at that time, but no ETA given as to when they might be fixed. I'm hoping sooner rather than later because I crash the game every single time I play at least once due to these bugs. I'm getting better at avoiding them but I still end up crashing it sometimes accidentally when I get very involved with researching inheritance chains and looking for people to marry into a title or claim.
https://forum.paradoxplaza.com/foru...g-if-arrange-marriage-is-opened-twice.839692/
https://forum.paradoxplaza.com/foru...crash-bug-in-title-claimant-interface.839628/