With Security Intelligence Update Version 1.387.1591.0 the inexplicable behavior is gone! Thank you!
Since March-2023 update of Windows Defender Quick scan takes long time!
Since March-2023 update of Windows Defender (Platform: 4.18.2303.8 | Engine: 1.1.20200.4 | Security intelligence update version: 1.387.740.0) Quick scan takes every third time 25 minutes instead of 5 minutes. Windows Defender is configured on my Windows Server 2019 to make one Quick scan per hour. The CPU usage in an normal Quick scan is constant, while in a long Quick scan it starts constant but after a 2 Minutes it goes down and sporadically it goes up for a few moments. No errors are reported in the logfiles! I already reverted the Platform and reinstalled it, but no improvements. Any ideas?