I don't know if it is that serious, however you mention that all works a-ok with line of sight IR. It's worth a shot to make sure your emitter(you didn't mention this if you are using one) is in the exactly the right place. I usually have to move them around to get them on the right location on that product.
If this above doesn't apply to you then please disregard.
regards, Mr. Willy
Some people are so used to special treatment--that equal treatment is considered discrimination..Thomas Sowell
