sounds like the "tree rats" have taken a liking to your shrub. i have seen them do this to mine on occasion, though it does not seem to be their preferred food most of the time.
deer will also browse the flowers and buds on mine.

the acorn crop last fall was very scant so that the squirels have been digging up the yard looking for anything and eating buds. We don't like to feed the things, but decided it would be better than letting them destroy other things. We got corn, still on the cob, which they don't really like, but they are eating it and leaving other things alone. We also make sure that there is water out. This keeps them from digging up bulbs.

Thanks for the responses. Squirrels are rampant in the garden so they could be the culprit. And we had deer last year but no deer damage this year so far (hopefully the deer have moved on to bigger pastures). Don't know whether wood rats are a pest here in the PNW but will find out!