Can a poorly connected XLR connection cause a reduced(less loud) signal?

Been chasing a gremlin. I have an XLR balanced connection between a ROSE HIFI 150b DAC/streamer and an Accuphase E-380 Integrated Amp.

I have noticed the left channel to be a bit quieter, less bright, and measuring a bit lower on the Accuphase’s DB meters. The problem has been intermittent. I feel like I may have solved it, albeit temporarily, by pushing the XLR farther into the connector on the ROSE HIFI. I had read on their forum site that those connectors could be problematic.

But the basis of my question is: Can a poor XLR/balanced connection result in a lower/softer sound?

I have experimented with switching the cable, and even bought a different cable, don’t believe it to be a cable issue.

Edit: yes, I know my post title is a grammatical nightmare.