Liable to forget one's problem (8)
I believe the answer is:
amnesiac
'liable to forget' is the definition.
(someone with amnesia has memory loss)
I can't explain the rest of the clue.
(Other definitions for amnesiac that I've seen before include "Experiencing a fugue" , "Forgetful person" , "Unaware of past" , "Memory-loss sufferer" , "One having lost their memory" .)