I've had both plants but haven't seen the same problem on both. The Siberian pea shrub had problems with leafhoppers. One year it suddenly didn't survive winter. Ferny leaves sounds a bit like something might be eating bits out of it? That wouldn't be leafhoppers because they don't chew.
Honeylocusts are always late to leaf out so I assume you're seeing something other than the newest leaves not having expanded yet? We had a thread yesterday about honeylocust pod gall midge. Any chance it could be that?
If you could post pics it would help.
