Gold Stereo - Disturbed Stereo Image - One louder than the other?

[Bbnsound]

Hi and happy Eastern everyone!

I am currently running a stereo setup with two Golds built in different years. However, one of both is louder than the other and hence centering is almost impossible. Anyone experienced the same issue?

Facts:

• 1x Gold with serial number M48XX (M = built in 2019, 48 = in week 48)
  
• 1x Gold with serial number L10XX (L = built in 2018, 10 = in week 10)
  
• The older Gold (L10XX) is getting way! hotter when playing music compared to the newer Gold (M48XX) which stays quite cool. So I assume there must be some physical difference between both speakers.
  
• I have already been using the older Gold (L10XX) for roughly 1.5 years while the newer Gold (M48XX) is just about two weeks old. However, I have not been using the older Gold very often.
  
• Both run on firmware 2.9.0
  
• Room is symmetric, speakers are set up symmetrically in the room (measured)
  
• I am sitting in the measured listening center.
  

Issue:

• The newer Gold (M48XX) is clearly dominant in the stereo image. It seems to play louder, hence centering is almost impossible. However, I am not sure if the volume is the (only) reason for the disturbed stereo image.
  

What I did:

• I marked the exact positions of the speakers in the room and switched the speakers. The stereo image was always distorted towards the newer Gold (M48XX). So the dominant side switched with the speaker. (When I did, I also switched the left and right channel in the app to ensure all parameters remained the same).
  
• I tried different positions of the speakers in the room, although they were set up perfectly symmetrical.
  
• I asked my brother to blind check several times which site is dominant and he always detected the newer Gold (M48XX) without doubts. I wanted to make sure I didn’t bluster into this perception although it was very! obvious to me.
  
• I set up my old Canton speakers on the same position as the Golds and I am able to center the same music very easily.
  
• I used music I know very well and of which I also know which instruments, voices, etc should sound centred.
  

Did anyone of you experience a similar issue?

Thanks a lot in advance for your input!