Good day, @AlexeyAB !
After the last commits mAP ceased to be considered.

He rolled back to the commit from Feb 20 and everything works.
This seems like a hardware error message. Try again with the last commit.
mAP is still not considered.
I checked all the commits, the error is in the March 11 commit.
Link to commit: commit
_It was at this commit that this error appeared.
Checked on two devices._
Do you get the same error message in all cases?
Do you use the same directory on HDD for all commits?
Checked on two devices.
On 2 different computers?
Or on 1 computer with 2 GPUs?
Do you get the same error message in all cases?
Yes.
Do you use the same directory on HDD for all commits?
No, on different computers, with different drives
Show content of obj.data file
Show content of obj.data file
classes=1
train=/home/dkubatin/learn_plate_20/train.txt
valid=/home/dkubatin/learn_plate_20/test.txt
names=/home/dkubatin/learn_plate_20/metadata/classes.names
backup=/home/dkubatin/learn_plate_20/backup
Can you successfully run object detection on video or calc_anchors?
./darknet detector calc_anchors obj.data -num_of_clusters 9 -width 416 -height 416
calc_anchors works, but the demo on the video does not work, writes: _Video-stream stopped!_
the demo on the video does not work, writes: Video-stream stopped!
Can you show screenshot?
Set in obj.data file
train=/home/dkubatin/learn_plate_20/test.txt
run calc_anchors and show me screenshot of result

Try to run mAP calculation with flag -cuda_debug_sync
He doesn’t count with the flag either, however, after the pull of recent changes, the map calculation works both with and without the flag.
Is problem solved?
Yes!