Is this fatal? 😟

No, it is not.
However it depends upon what exactly it is and the plants culture. It could simply be the result of either water sitting for too long in the new growth or the result of a very minor insect attack. I can't tell which would be the case.
It appears to Me to be a Dendrobium phalaenopsis orchid. NOT to be confused with a Phalaenopsis orchid.
Yours needs to be grown warm, 60-70 at night, 78-85 during the day. It should get three to four hours of sun, watered well and then allowed to dry out a bit before watering again. It needs good air movement, feed it every three months with just a little fertilizer at 1/2 tsp per gallon.
If water sits too long and heats up, it can cause this blackened damage that you are seeing.
This type of orchid does not hold all of its leaves from year to year either. But as long as the pseudobulb is firm and green, it serves a purpose.
Join us here at the NGA Orchid Forums!

Thank you SO much!! I have had this plant for many years. But it's been through a lot. We moved to NC about 4 yrs ago from South Florida. For me it was easy to grow orchids there. This was small when I tied it to a tree branch and it just kept growing. My husband cut the tree branch so I could bring it with me. 😊 It has been in a greenhouse for two winters, this winter I kept it inside under grow lights. It's now outside under protection for only a couple of weeks and this problem is new. It does have some new growth. It probably got too soggy. I will adjust things and be mindful of your info, and see what happens!! I really need to get a new piece of bark to attach it to. Any suggestions where I can buy something to attach it to? I haven't been able to find anything. 😊😊 thanks again!

On line at Green Barn Orchid Supplies. Just google them.
If you could find any local dead or trimmed sassafras or cedar limbs, they work well.
Sometimes at Lowe's or Home Depot I have seen Cork bark which is good too!
You're welcome!