Did a bit more digging in the way GIMP works. Same thing used to happen when GIMP used to create a tiff output file. However, if I unselect the option of saving xmp data GIMP does not combine the tags in one tag. Perhaps there is a clue there! If ART can suppress the xmp data in the file it sends to GIMP things would work seamlessly! Hopefully!! Thanks for your patience and support. Appreciate it a lot. Uploaded a screenshot of the output options in GIMP.
If the metadata that ART generates are correct, this is a problem on the GIMP side, and “fixing” it on the ART side is not the way to go.
On the other hand, as I wrote above, if you have evidence that ART generates wrong metadata, then I’m certainly willing to fix this.
HTH
It’s hard for me to say where the problem lies. I created a tiff file from within ART and checked the metadata using ExifT ool. However, not being very conversant with how different programs treat metadata, am unable to pinpoint the source of the error. I am assuming that the tiff file sent to GIMP from within ART is the same file which ART saves through the “Save current image” option. I am have uploaded the tiff file. If you feel like it you can check the metadata generated by ART for that file. It’s not a showstopper. However, if it works out, my work flow is that much more streamlined.
The metadata exported from the ExifTool is attached below.
Again, I would not insist on you spending more time on this problem. For me it is more of an academic curiosity!
Looks like the version 1.11 is out! 
Any difference between the version you shared with me? I have a 9th generation CPU which I think is Coffee Lake. Since I do not see this listed, I guess I should be downloading the generic version.
I am using the portable version. Should I just unzip the archive in the program directory?
I am again able to build ART 
After reinstalling MSYS2, carefully checking for dependencies, rebuilding Mimalloc, libraw, exiv2, lensfun , modifying build flags, that seems ok.
Version: 1.11
Branch: master
Commit: 3adbd237e
Commit date: 2021-11-30
Compiler: gcc 10.3.0
Processor: Skylake
System: Windows
Bit depth: 64 bits
Gtkmm: V3.24.5
Lensfun: V0.3.95.0
Exiv2: V0.27.5.2
LCMS2: V2.12
LibRaw: V0.21.0.Snapshot202101
Build type: release
Build flags: -fno-tree-loop-vectorize -std=c++11 -march=native -Werror=unused-label -fno-math-errno -Wl,--stack,4194304 -Wall -Wuninitialized -Wno-deprecated-declarations -Wno-unused-result -fopenmp -Werror=unknown-pragmas -Wno-aggressive-loop-optimizations -DNDEBUG -O3 -ftree-vectorize
Link flags: -march=native -s -O3
OpenMP support: ON
Mi-malloc: V1.7
Build OS: Windows
Build date: 2021-12-03T10:23:14Z
Different ART 1.11 optimized Windows builds can be found at ART-W64NightlyBuilds/ – Keybase.pub
Great! I downloaded the generic version. I am using ART from a flash drive and have set “MultiUser=false” in the options file.
A question. I have changed some of the preferences in the current portable installation apart from the above option. If I overwrite the installation directory with the new version, will these custom changes be lost?
The generic build will have about the same performance as the official build. You could try a build adapted to your processor, which can provide some improvement.
I don’t remember where the options file is located in a portable installation. I think it is created and located in a specific folder inside the installation directory. so Before extracting from the zip, I would save the preferences and copy back.
The options file is in two places. The ART program directory and the mysettings directory. Both the files have MultiUser setting and I had to set the “MultiUser=false” option in both the files. Better would be to have this option in only the file in the mysettings directory. Since this file is never overwritten when the files are extracted from the archive, the portability will survive upgrading. Another option would be to override the “MultiUser=false” option from the program directory with the one in the mysettings directory if one exists. I hope I am making myself clear 
I cannot really help as I never use the portable feature.
I think that the multiuser parameter is read from the options file in the program directory. All other parameters are read from the options files in mysettings or from the configuration folder depending on multiuser.
So when upgrading, it seems you need presently to set the multiuser parameter again in the program dir options file.
Perhaps if an options file exist in mysettings, the app should stay portable.
You could submit this idea to @agriggio
I find the generic version a bit laggy. My processor is Coffee Lake. Don’t find that in the list of downloads. Anything closer to this processor?
Skylake should do.
Thanks.