Redstone works a bit different across Java and Bedrock, but some features should work the same.
When you place a redstone block on the side of a comparator to only let signal-strengths of 15 pass through the comparator, it still lets through all signal-strengths because the comparator ignores the redstone block, and only looks for dust or other comparators pointing in its side.
When you do the same on Java, signal-strengths lower then 15 get cancelled out.

Steps to Reproduce:

1. Place a comparator in compare-mode (third torch not turned on)
2. Feed it a signal-strength of 14 from the back

1. Place a redstone block on the side of the comparator

Observed Results:
The signal of strength 14 carries trough the comparator.

Expected Results:
The signal gets blocked by the redstoneblock (which carries a signal-strength of 15), like it does on Java.

Screenshots/Videos attached: 

Grass: Bedrock (1.20.12)
Sand: Java (1.19.4)

{}

Notes:

The mentioned versions are those in which I could test. If Bedrock had a way to officially switch versions, I could check if this behaviour is the same throughout all versions, which I suspect.