When removing SSL support by using /opt/lampp/lampp stopssl and then restarting xxamp with /opt/lampp/lampp restart an entry into the error log is as follows:
[warn] Init: Session Cache is not configured [hint: SSLSessionCache]
I managed to fix the error by commenting out
LoadModule ssl_module modules/mod_ssl.so
I hope this helps someone who is looking for it.
Not sure why when you use stopssl it doesn't remove loading the mod_ssl.so module on subsequent starts and restarts.