There was no mention of oak leafrollers in our PNW Pest Management Handbook for Insects. Without a picture or a sample it's hard to make a definitive diagnosis. It may be https://pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/oak-quercus-oak-skeleton...  the link notes that natural predators will keep most populations in check and the use of broad spectrum insecticides is discouraged as it can harm beneficial insects.

That doesn't mean it's not https://en.wikipedia.org/wiki/Archips_semiferanus but it would be important to obtain some samples and take them into one of the Master Gardener office locations (http://extension.oregonstate.edu/mg/metro/questions) We are one of the first lines of defense in identifying new species that have migrated to our area. I found this article from  UC extension http://ipm.ucanr.edu/PMG/PESTNOTES/pn7473.html which discusses leafrollers in general (there are different types which affect different plant species.)

Most mature plants can withstand damage, the issue comes in if the pest overwhelms the plant or there is multiple year impacts that eventually weaken the plant.

Here is a photo of one of the little worms.

Let me know what you think.

Thanks!

Bonnie