This year my rhododendrons have brown and curled leaves in places. I pruned these off. Any idea why this happened?

Question

All my neighbors’ plants look the same.

Answer 1

Damaged and curled leaves could indicate pests or disease.
It also could be Winter Burn, as you mention neighbors appear the same.

These links will help you.
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/issues-with-rhododendrons.htm
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/pruning-rhododendrons.htm
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/yellow-rhododendron-leaves.htm