Open Help for LO Basic.
Search for function InStrRev.
Code-example of German help:
iPos = Instr(sInput,"eine",13,1)
iPos = Instr(sInput,"eine",13,0)
Function is wrong, must be InStrRev instead of InStr.
Olivier Hallot committed a patch related to this issue.
It has been pushed to "master":
tdf#112391 Fix inStrRev in example of LO-Help