Maximum Lines of one Function Library File (QFL File)

I met a case when you developed a script with Function Library with more than a thousand lines: when you call a SUB or function, UFT will get to random lines from the Function Library

For Example
I call SUB named CreateUser in from Function Library SUB_User.qfl. The SUB is located at line 5400 from 16000 lines. UFT will get to line 8000.

The solution I get is to reduce the line, moving the SUB or Function to a new Function Library. Until the last I get to 3000 lines in one Function Library file, UFT works normally.

So are there limit lines in Function Library that we have to check for UFT work?