I'm riding a hybrid with 48/36/26 chain ring and 9 speed 11-32 cassette.
When I change up OR down at a specific point the shift is slow and doesn't always engage. On the 48 this is between the 21 and 19 cogs and on the 36 this is between the 24 and 21 cogs. Note that this is rear change only and both up AND down shifts.
Every other change is clean and quick.
Any ideas gratefully investigated as these changes are right in the "daily range" I use for commuting!