Yes. I did the check in two different systems. It was consistent. And attributable to the amps. If you did an incorrect assessment that's your problem.
I have no problem in disagreeing in audio matters - for me it is part of the hobby. I have experience enough with Nagra to know that such opinions on those particular weaknesses based on listening in two anonymous systems should be taken with care.
I considered the Nagra HD for the XLF's after trying the Classic at my system. The experience did not proceed because the HD preamplifier was not available for demo at that time and considering the weight and size I postponed it until I could try the whole system. Meanwhile the system changed ...
Nagra often shares demos with Wilson. Although all reports should be taken with many grains of salt, interested people can immediately find plenty of opinions on the Nagra's bass performance just googling the two brands.
And no, I am not buying Nagra ...