Lparallel randomly stopped working

[K1D77A]

I'm really sorry that this is going to be vague but I dont have any other info to give you, but I have a program that has been running for a long time, about 10 days ago a feature of the program stopped working and I have just worked out that it was because every called to a lparallel provided mapping function was completely blocking:

; Evaluation aborted on T
RSS> (lparallel:pmapc (lambda (x) (print x)) '(1 2 3 4))
; Evaluation aborted on T
RSS> (lparallel:pmapc (lambda (x) (print x)) '(1 2 3 4))
; Evaluation aborted on T
RSS> (lparallel:pmapcar (lambda (x) (print x)) '(1 2 3 4))
; Evaluation aborted on T
  0: (ERROR #<UNDEFINED-FUNCTION *KERNEL* {100A38A143}>)
RSS> lparallel:*kernel*
#<LPARALLEL.KERNEL:KERNEL :NAME "lparallel" :WORKER-COUNT 2 :USE-CALLER NIL :ALIVE T :SPIN-COUNT 2000 {100646C253}>
  0: (ERROR #<UNDEFINED-FUNCTION KERNEL {100E49FFB3}>)
  0: (ERROR #<UNDEFINED-FUNCTION KERNEL {100F62F8E3}>)
  0: (ERROR #<UNDEFINED-FUNCTION KERNEL {1005F18273}>)
RSS> (lparallel:end-kernel)
(#<SB-THREAD:THREAD "lparallel kernel shutdown manager" RUNNING {1005F1DAE3}>
 #<SB-THREAD:THREAD "lparallel" RUNNING {1000DC03E3}>
 #<SB-THREAD:THREAD "lparallel" RUNNING {1000DB9093}>)
RSS> (setf lparallel:*kernel* (lparallel:make-kernel 4))
#<LPARALLEL.KERNEL:KERNEL :NAME "lparallel" :WORKER-COUNT 4 :USE-CALLER NIL :ALIVE T :SPIN-COUNT 2000 {100B9FCC13}>
RSS> (lparallel:pmapc (lambda (x) (print x)) '(1 2 3 4))


2 4 
1 
3 
(1 2 3 4)

I had to manually kill the kernel and start it again.
I'm sorry I can't provide anymore information.
Thanks.