Level mismatch in speakers when using tube amp

I’m having a strange speaker level issue in my system and wanted to see if anyone had some suggestions. I recently purchased a pair of Polk Lsim 703 monitor speakers for a great price and wanted to hear what they could do after reading comments and reviews about how nicely they scale up with decent electronics. I hooked the Polks up to my Primaluna Dialogue HP amp and noticed the level of one speaker was much lower than the other. I then switched sides by moving the left speaker to the right channel and vis versa. The level mismatch followed the speaker. I tried both the 4 ohm and 8 ohm taps of the PL but same results. I even tried replacing my 7581 power tubes back to the stock EL 34’s, same results.

Great, I thought, something wrong with a driver, crossover, something in the one speaker. I can correct the issue by adjusting the preamp balance but I have to adjust it pretty significantly to get the image centered. When I do that they sound really nice albeit at a lower level than normal based on preamp volume setting.

Then I decided to place the Polks in my other system which is a solid state Yamaha AS3000 integrated amp. Both Polks work perfectly when connected to the Yamaha and actually sound great. Full sounding, a little warm with good but not great detail, a bit of a surprise none the less. What’s strange is I have three other pairs of speakers of various brands that all work perfectly with both the tube system and solid state system. What could be going on with the one Polk speaker that isn’t playing nice with tubes? I was going to send an email to Polk tomorrow and see what they recommend but would like to hear your opinions.
Thanks everyone.

System:
PS Audio Directstream jr D/A (Streaming Tidal)
PS Audio BHK preamp
Primaluna Dialogue Premium HP amp
Yamaha AS3000 integrated amp
Acoustic Zen Absolute and Analysis Plus cabling