Brush settings affecting all brushes? Urgent help needed please~

Hi guys,

Lately I've had this issue where all my brushes are sharing the current brush settings regardless of their unique settings they were saved with.

For example, I just created a new brush, all new unique settings, locked the settings, saved as new preset, even exported it, and put it in my psd brush preset folder just in case.

The brush works perfectly whilst in use, but when I click to a different brush (originally with different settings) the settings just remain the same as my previous brush, all my brushes are just reflecting the current settings.

I've re-set the tool/brushes to see if that helps, it just deletes all settings, so the new brush I made now has no brush settings, when I click to another older brush they also have no settings...until I change the settings manually again, and all paint brushes will just reflect those new settings. 

It appears that my brushes have somehow lost the ability to reflect their unique settings, all brush tips basically remain the same, so the shape is there, just everything else (transfer/color/smoothing/texture etc) is being over-ridden for all brushes, it's extremely frustrating as none of my brushes are working as expected now, unless I somehow remember their unique original settings and change it every single time I use the brush, which I've never had to do in the past.

So saving brushes with unique settings has kinda become redundant as the brush won't reflect them if I change brushes/settings for another brush (which most of us do constantly, as that's the beauty of creating new brushes) 

Please help, I've spent days trying to find a solution 😕😕 

Currently running an iMac Catalina up to date and Photoshop 2020 up to date~

Note: I used PSD 2019 on a family member's computer, loaded my brushes, and everything seemes to be working fine, so I have a feeling it's a psd 2020 thing - might it be a bug? 

Thank you~