Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There was a bug in the way that wrapped border values were being copied. Essentially, it is necessary to make sure that the first row has had its border (padding) values copied to before setting the entire last row to be equal to the first. The way it was being done lead to cases where the first row was copied into the last before the first row had been "completed". This bug showed up intermittently, because it depends on the order in which TBB chooses to run the sub-ranges.
I made an example showing how the new algorithm works: https://godbolt.org/z/qcoEEvsKn
The only difference is to explicitly copy the first row into the last row after all the "non-last" rows have been completed.