Pine Lakes in Myrtle Beach was designed by Robert White in 1927. At some point in the past 10-15 years (I think) they eliminated a couple of holes (I believe to either build a new road or expand an existing one) and built two new ones as replacements. The new holes aren't bad, but they're out of character with the rest of the course. It's easy to tell they were built separately and they really mess up the overall flow. It feels like you wandered off onto a separate golf course.
I agree with the "out of character" problem. At my club that is solved by the new holes being one and two, so you get then out of the way first and then on to old ones, 16 in a row.
In the case of Carl's club, Carolina Golf Club, Kris Spence did a wonderful job using newly acquired adjacent property to route a constantly bending par 5 followed by a shortish par 4 over the corner of the new irrigation reservoir solving both the club's irrigation supply issues and creating space for a much needed practice range on the back-to-back par 4s that used to be holes 1 and 2.
In the case of my current facility, Idle Hour CC, holes 7 and 8 were added nearly 60 years ago on previously adjacent property. It is my understanding expansions to the clubhouse and its amenities at that time claimed portions of the original 1st and 9th holes creating the need for two holes elsewhere. The par 5 8th may very well be one of the best non-original Donald Ross holes I've ever seen. If you didn't know the hole was not an original Ross hole you would never guess. Kudos to whoever routed the hole originally and to Ron Prichard for the current iteration.