Spark Level 21 Has the Same Damage as Spark Level 20

I recently obtained a corrupted Spark gem with +1 level (making it level 21). When equipped, the tooltip displays a final gem level of 26 due to my wand providing an additional +5 levels. I also have an old Spark gem at level 20, which shows a final level of 25 in the tooltip. However, the damage output for both gems appears to be identical according to the tooltip.

This seems to indicate that the additional level from the corrupted Spark gem isn't affecting the damage as expected. I've attached screenshots to demonstrate the tooltip for both level 21 and level 20 gems for comparison.

https://imgur.com/a/oVT9OyL

Also true for lvl 21 Shockwave totem.

Same experience here for Spark.

The gem says more damage. About 12%.

The DPS tooltip doesn't increase at all, though.

Same for all +1/-1 vaal corrupts , they do nothing.

Any updates on that? I already bought 3 different sparks just to know that they are all work than my lower level spark