Is now the right time to buy a Garmin fenix 6 sapphire?

Buy stuff when you need stuff. If you ask this kind of question, then I don't think you really need it... 

Ive had mine a few months now after upgrading from Fenix 3HR and love it. However, there's an issue with the wrist heart rate sensor that struggles to keep up with your heart rate. 

This is the only issue i have with the watch, everything else is perfect. 

Here's the link to others experiences with this issue. 

https://forums.garmin.com/outdoor-recreation/outdoor-recreation/f/fenix-6-series/195729/anyone-still-having-heart-rate-accuracy-issues-with-their-fenix-6/1055699#1055699

Amazon sometimes has the Fenix line on sale.  Maybe like 50 bucks off or something but money saved is money earned. Right now they're not on sale so I'd wait.  I'd tell you to just buy it now but since these watches do go on sale from time to time, just buy it then.  

Yes.  Maybe. Maybe.

Sales of the Garmin Fenix ​​6 have begun.
Many sellers have discounts.
Could this be a sign that a new model will appear soon?

Not sure why there would be a new model now, the Fenix 6 is not even a year old. However if you're looking to buy the current $150 discounts (if in USA via Garmin.com) are good, unless you can get the 20% off via your employer/health care provider.

In USA is very good discount. But in my country there is 50eu discount..Europe, Lithuania. Its little sad.. I think it Could be better sales..

Could this be a sign that a new model will appear soon?

More a reflection that retailers need money. COVID-19 is likely affecting retail quite heavily.

Yep i think in few months we will get new watch, and problems with old watch will stay. Never ending story.