Is this intentional or an oversight?
Well, neither. It’s applying the simplest form of expanding/shrinking as it was present in old trackers. When taking delay values into account and especially when shrinking, the conversion can be tricky, because new columns may need to be created to deal with overlapping notes after shrinking. We simply never spend time with this, but may do so in future, if that’s something that many people request.
In the meanwhile, you can use dblue’s flexible pattern resizer tool for that.