I had the same issue using 6.4.1 forwarder except it was high CPU.. I opened a support case and they confirmed it was a bug in the 6.4.1 forwarder and recommended I use an older 6.3.6 forwarder
Case # 378231
Same question on which reference, I noticed Linux 6.3.3 UF works fine but our Wintel 6.4.1 UF gives sometimes unbelievable CPU load on quiet test servers. And wondering to which 6.4.x or 6.5.x is now the best option.