Annoying fret buzz

[Maurice Hason]

Hello, it's been a while since I was on board and I would like to ask a professional opinion before making any changes to my bass.

I purchased my BT6 five months ago, new, and it played excellent, very low action and not fret buzz at all.

Unfortunately, due to a family tragedy I didn't play at all for 2 months.

Now that I picked up the bass again, I have a buzz between frets 10 to 15. It sounds like the notes are chocking.

This is mainly on the C and G strings, but also appears on the lower strings but less severe. On the C and G strings this is really annoying and unplayable.

I assume this has to do with climate change, temperature and humidity, and it can probably be solved by tuning the neck. I am comfortable with tuning the neck, I always setup my basses on my own, but I wanted to be sure before making any changes.

Observing the neck relief from the tunes down to the body, it has a vary small bow on the B-string side, and even a smaller (almost flat) on the C-string side.

Thanks in advance,
Maurice