CPR grade axis breaks for single day zoom

[Arzorth]

I was having a look at my CPR graph and zooming in one of the days, it didn't showed the grade axis I would expect:

https://www.thecrag.com/en/climbing/world/ascents/by/jositogg/has/gym-sport-cpr/view-between/2022-6-6+2022-6-6/between/2022-6-6+2022-6-6?sortby=rating,desc

The expectable grade scale for the graph would be from 6c to 8a, but it is showing from ~4c to 8a.

Regards!