Bug when improving gloves(core skill)

Hi all
Before patch 1.2.3, when upgrading gloves to +5, I always received +4 to the main skill, regardless of the initial parameter (+2 or +3)
After patch 1.2.3 this does not work

this function was added in patch 1.2.0:
Skill Rank and Passive Rank affixes that roll at +1 now upgrade to +2 when at five Item Upgrades, rather than remaining at +1 (higher base rolls are unaffected).

is this a bug?

This fix was to add a second point to items with +1 skill roll. Prior they would stay at +1

If you have a +2 it becomes +3 (same as prior to this change and +3 becomes +4

The change was only to the +1 as it never increased before.

This never worked like that