Action partially closes after opening...trouble loading lower barrel

New to the forum and new to a Savage 555 in 12 gauge. It was my late father's shotgun that was a warranty replacement back in 2018 from a model 512 that could not be fixed. I recently acquired it and I noticed that when I open the action, it opens all the way but then "detents" back to a slightly closed position that does not allow me to load another shell. I can keep the action fully open with two hands, but it wants to just slightly close after full open half of the time when opened "normally".

Before I go oiling here or filing there, can anyone comment on a fix for this? Do I need a new "plunger" on the forearm end of things? Let me know if there is some adjustment I can do.

Thank you.