Update:
I got a response back from tech support from the Boss website, they suggested performing a Factory Reset on my Katana amp, which I have just done, so far it seems to have fixed the issue I was experiencing with my Katana amp, I'm going to do a check to make sure it is fixed by leaving the amp powered-off overnight tonight and I'll try powering the amp on again tomorrow.
Apparently the cause of my issue was a certain effect remaining locked-on or something, here's the response I got in my email from tech support at the Boss website:
Hi Simon,
Have you performed a factory reset on the unit?
KATANA MK1 and MK2 FACTORY RESET - 50 / 100 / HEAD / ARTIST
It sounds like a certain effect might be locked on or something here and this would clear it up.
Kind Regards,
Braedon
Technical Support Representative
Roland Customer Support
If anyone else is experiencing the same, or similar issues with their Katana amp, here's how to do a Factory Reset:
https://rolandus.zendesk.com/hc/en-u...0-HEAD-ARTIST-