Howdy! I'm hoping to tap into the collective Savage 99 knowledge to help me figure out how to fix the following problem with my 99a .358

Background info
I bought this rifle a few years ago from a fellow Texan, almost unfired condition with a sweet old Weaver K4 on it. Fired it once or twice from the bench - couldn't get it onto the paper using the scope - ran out of windage - figured there was an issue with how the weaver bases were mounted. Let it sit in the safe until I had time to dive in......that was 3 years ago.

In preparation for a public CO elk hunt this fall I've replaced the scope base with a Leupold 1-piece and mounted a VXR 2-7.

Finally had the chance yesterday to spend some time sighting it in. This is the first time I've shot more than a few rounds with this gun. Am extremely pleased with 3/4" 100 yd groups with Hornady 200 grn factory loads. Will try 225 grain Buffalo Bore next.

The problem

Yesterday I noticed that each time I fired a round the tang safety would reset itself back into the SAFE position so that I couldn't open the lever to eject the spent casing (was using a Caldwell lead sled for sighting).

Clearly this will be a problem if a follow up shot is needed.

The safety seems to have some sort of detent ball underneath it as I can feel it bump over something when sliding it forward to the FIRE position.
But it isn't super smooth, doesn't go all the way forward into FIRE sometimes or go all the way backward into SAFE when manually sliding it. But always seems to reset to SAFE when fired.

Have had my 99R .308 apart so and am comfortable taking the 99a apart however as y'all know the safety is different on the 99R.
Hoping to get some info before I dive in for an exploration.

Anyone ever experience this and if so what was the fix?
Anyone have suggestions on what it could potentially be?

Thanks in advance!