Mine has the exact same issue as RX25SE seat.
It happened to mine as I improperly reassembled the seat after doing some work on it...
Or it just snapped at that spot. Its just a spot weld iirc.
I'll get around to fixing it one day and can do yours too if local to me in Melb.
Seat removal is easy: but take care to put the window down & to cover the door cards with a doona/s as the seat mounts wreck the armrests/cards.
Also take care to remove all the plugs.
A 12v power supply is handy for moving the seat base into the right position to enable the seat base to be unbolted.
You'll need a decent wrench/socket/ratcheting with wobblers kit to do it and a ton of patience.
The base will probably need to be stripped in order to be welded, if you break a hog ring, a zip tie can substitute
PS I didnt need to do anything much to the seat back, I just attacked the base.
OR: or could just be the motor has a sticky brush or is filled with brush dust, a common issue with older Libs.
The solution can be as simple as the technical tap to loosen the brush or remove the motor, open inspect and clean.
Reassemble with care : I had to make a wee wire jig to hold the brushes in place whilst replacing the core.
Let me know if you need more help.