There is minecraft:purpur_block and consistencyplus:purpur_block

Minecraft purpur was renamed to cut purpur:

and a new purpur block was added:
https://raw.githubusercontent.com/ConsistencyPlus/ConsistencyPlus/master/src/main/resources/assets/consistency_plus/textures/block/purpur_block.png

Yes, like DragonEgg said, the Purpur block added by Minecraft is changed to be the Cut Purpur block in Consistency+

Some people may ask "Why dont you just change the texture" which is a valid argument, however, we didnt want to change how structures from vanilla, other mods, and player made ones looked.

Theres more blocks that do a similar thing, it IS intentional, so Ill close this issue, if you have more questions, feel free to talk about it in discord or in discussion.