requester.class occasionally fails to open

I discovered that when using OS 3.2 requester.class requesters in a ReBuild GUI builder-generated project, requester.class rather often fails to open, especially if I use more than one requester in a project. The phenomenom isn't bound to the use of a certain compiler and happens with m68k-amigaos-gcc, vbcc and SAS/C alike. It happens with small data and large data compiler options aswell. Up to now, I could not find out about the reason.
The following project source (see link) uses bebbo's amiga-gcc. Compiler call is
m68k-amigaos-gcc -Wall -s -Os raip.c -o raIP -lamiga -lsocket -noixemul

Link: https://pastebin.com/m8BvAzTW

Compiles fine, but program refuses to start due to not opening requester.class until the class was opened by some other app that uses it.

Any ideas how to fix this behaviour?