And thumbnail is generated in DOpus but not in Explorer. Picture in question is in JPEG XL format and it seem that it is handled by JPEG XL Viewer Plugin 0.0.0.4 (picture is not shown in Viewer if the plugin is disabled in Preferences).
Directory Opus Pro 12.33 Build 8659 x64
OS 6.1 (B:7601 P:2 T:1) SP 1.0 "Service Pack 1"
Picture is attached in thread: