Don't know if this bug was in LP8, but in LP9 I've been hair tearing over some long samples in exs just cutting out. There is a fix, if you own Redmatica's excellent Keymap editor... simply make sure that you have the exs "options/open in external editor" set to Keymap, then sen the offending instrument to Keymap & back again... samples now play there correct length.
Chiz
Chiz