Going round a bend slowing is activated mechanically by a brass finger touching the rail in the top trunnion which connects the yellow black wire to gnd through a switch above the finger.
From what you’ve detailed its more likely to be a wire break in the bottom loom or possibly a bent charge pickup rod on the lower trunnion. There is a slowing switch activated by the charge pickup rod which only becomes active after approximately 1m of travel, hence it can initially pull away from a limit and continue at full speed but when its activated during travel it will slow and eventually stop even if it doesn’t reach the travel limit. Simplest way to check is to release and reapply a call when it starts to slow on the bend, if it goes back to full speed then highly likely to be a broken wire in the loom.
