The phrase "a disappointing but" is correct and usable in written English.
It can be used when introducing a contrasting idea or statement that follows a disappointing observation or experience.
Example: "The movie had a disappointing but intriguing plot twist that kept me engaged until the end."
Alternatives: "a frustrating yet" or "an underwhelming yet".
Has also been a disappointing but staying-on sixth in the shorter Becher Chase over these fences.
In that sense, it was a disappointing but not unsatisfactory New York encounter with the eccentric genius from the Twin Cities.
It was a disappointing, but perhaps not surprising, turnaround to the day's trading, in which the three main stock indexes posted slight gains most of the day before losing steam.
The lending figures for Project Merlin do not yet indicate an improvement in credit conditions for small companies – a disappointing, but not surprising outcome given where a range of surveys having been pointing.
Carolos Carvalhal's first full season in charge may have ended with a disappointing but deserved play-off final defeat, but we have an attractive style of play and the players are accustomed to their roles.
She made up the distance and nudged ahead to give the United States -- missing two of its top sprinters, Gail Devers and Inger Miller with hamstring injuries -- a disappointing but respectable third.
Of his batting Wisden said "Trott's average is a little disappointing, but when a special effort was required he was not often at fault".
This is our 2nd busiest earnings week and, so far, they've been a little disappointing but not a train wreck..
A disappointing delivery, but a delivery all the same.
A homeowner may challenge a disappointing appraisal but, Ms. Cohn said, "lenders hardly ever change their mind".
His time was a disappointing 2 58 54, but he is determined to improve.
