Try turning the harmonics dial down to almost zero. 0.2 works for me. This default went up significantly with firmware Q5 I think.
This muddied the hell out of all my presets.
Then for Q6, the default preamp tube type changed from 12AX7A to the 12AX7 SYL.... I didn't like this at all either. In fact I rolled firmware back to Q5.
In general I struggle with all firmware updates, I'm a "deep amp parameter" fool.... I like to go chasing artists tones and need to really tweak the hell out of the amp block to get there. I'm not happy unless I can get the tone spot on, and I mean EXACT. Eventually I get there (this product is ridiculously good for this) The down side is, it takes hundreds of hours to get there... And that means each firmware is a disaster at first and quite often I give up and roll the firmware back.
Looking at all the comments on this forum, when a new firmware comes out, I see that around 95% of the posts are in absolute awe of the new firmware and how much "more real" it sounds etc, (I have to wag my head in disbelief here actually) But then it occurred to me, maybe most users don't go chasing exact artist tones and don't go changing the finer parameters in the amp block, and therefore use the amp pretty much default.....Then the amps may well sound better.....Better at default. Many guys reset the amp block....but that's suicide for me.. At least for they way I like to use the product.
All of that said I did feel Q5 was the best yet - I stuck to Q1 before that, even though I tried 2,3,4, and rolled back. It's the first firmware I have been able to dial all my artist presets back in, and they now sound spot on to me..... I had to turn the Harmonics dial down though