Radius filter on execute not working as intended.

Partner Rank:
1

Verification Builds:
1.16.20.02_rc3 (4466288, W10)

Regression Builds: 1.16.10

Summary:
We've discovered that one of our maps doesn't work on 1.16.20 but did work on 1.16.10. We are in a situation where we know how to fix the issue but don't know what is actually causing it to break between versions.

There is a function in the map that runs this command: 

execute @s[tag=tester] ~ ~ ~ tag @e[tag=other,r=0] add found

Which no longer works (the tag found is never applied to the entity), but changing the r value to 1 fixes the issue:

execute @s[tag=tester] ~ ~ ~ tag @e[tag=other,r=1] add found

The entities are at the exact same coordinate so the second entity should be targetted with the r=0 value. 

We believe this issue is related to MCPE-62142 and MCM-926.

Affects currently Live Content:
Yes

Impact:
Detection logic is broken and is impacting live content

Repro Steps: N/A

Observed Results: The tag 'found' isn't added to the second entity.
Expected Results: The tag 'found' should be added to the second entity.
Screenshots/Videos: 2
Notes: N/A