take a look..(DS41262C-page 210)

"If the GIE bit
is set (enabled), the device executes the instruction
after the SLEEP instruction, then branches to the interrupt
address (0004h). In cases where the execution of
the instruction following SLEEP is not desirable, the
user should have a NOP after the SLEEP instruction"

...did you try

@ sleep
@ nop

?

I'm not expert neither....