Help with a finicky buckling spring

[mrb5217]

I have an IBM Model F122 that I've put back together after disassembling, cleaning, replacing the foam, converting to ANSI, etc.

I have one key (my right arrow) that is being finicky, and I'm looking for some suggestions as to what it may be.  It feels like the spring seems to unseat itself from the little post inside the keycap causing the buckling action to not work correctly, but I have no idea why or how to fix it.

After putting the keycap on it is fine, but then after sitting for a minute or so, keypresses do not register and the buckling sound isn't as sharp.  Press on the key a few times and it realigns itself and is ok again.  The spring is straight, no kinks, the ends are flat, and it seems to be the same as all the other springs around it. 

I tried swapping keycaps with another key that works fine, removing the floss mod, and even pulling the spring off, stretching it out a little, and putting it back on, but no change.

Any ideas?

Sometimes it's fine:
https://vid.me/771w5

And sometime's its not:
https://vid.me/kkmXV

Thanks,
Matt

[fohat.digs]

Trade the key stem for another one from a less-used location. If the stem itself is defective, that should help.

[mrb5217]

I guess I should have used the right terminology.  When I said I swapped the keycaps, I meant the stems.  Didn't change the outcome, and the "bad" stem worked fine on other springs.

Doesn't really leave much other than a bad spring I guess.  I ordered a new hammer/spring on eBay and see if that helps

[mrb5217]

I made a chopstick tool to change the springs today and tried swapping springs with another good switch, but no change.