Previous OpenBlas patch fixed the crash with Sophos (see reports #3633 and #4246) but created a huge slowdown of startup because of a timeout change and most likely OpenBLAS being loaded at startup during the various verifications. A new patch has been merged upstream to lower this timeout to something more reasonable. Reporters confirmed GIMP now runs fine (neither crashes nor very long startups). See: https://github.com/xianyi/OpenBLAS/pull/2339