Costal Redwood Sunburn or Other Issue?

I’m wondering if my Costal Redwood is experiencing sunburn or some sort of other issue such as a fungal problem?

Some context and background to my situation:

The tree was repotted last year early spring and absolutely exploded with growth during the entire growing season. Even late into the season I was seeing new growth at the top (what you’re now seeing as a brownish orange). This winter I’ve been using a new over wintering process which I think is where my problem comes from. I built a greenhouse to fit on my apartment balcony and while it works great, its a little short so the top of this tree was pressed right up against the greenhouse plastic. Up until about February the greenhouse wasn’t being hit with direct sunlight due to the positioning of my balcony but once it hit is when the tree really started to turn.

In the fall I sprayed it with lime sulfur before putting it away for the winter and we did a check for spider mites yesterday and didn’t find anything indicating that was the problem. This tree took a lot of water over the summer so I made sure that anytime I noticed the soil dry during the winter to give it a good drink when the temperatures allowed.

A lot of this seems to be pointing to sunburn / possible wind burn since when the top of the greenhouse was opened it was exposed. Other note is there are green buds dotted throughout the tree so I’m hoping that is a good sign. Just wanted to get others thoughts to possibly help alleviate some anxiety as its a very cool try that I would rather not lose.