I got the above error by rotating a merged chest wired directly or indirectly to a shortwave radio. All wires connected to the radio disappeared.

Blueprint to reproduce (requires Merging Chests and Wooden Chest selected in startup; use Merging Chests rotate hotkeys):

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

Edit: Copy-pasting radios with wire connections to most entities (combinators, inserters, pumps, vanilla chests, train stops) breaks the wires now. No special blueprints are necessary to reproduce this.

Blueprints and copy-paste seem to work fine for me, even with Merging Chests. Could there be another mod interfering? It does appear that you cannot place a Merged Chest blueprint manually, only by robot.

It happens when placing blueprints of (or copy pasting) radio <-> wire <-> entity in editor mode with "instant blueprint building" checked. Both in Editor Extensions and freeplay /editor when EE is not installed. Bots connect the wire properly, it's more of a design inconvenience.

Ah, that's a special case I hadn't tested. Thanks for clarifying. It should be fixed now.

The wires connect now as long as the blueprint is in my inventory :). I'm guessing the mod would need to access the library to connect from there.

The fix I made checks to see if the entity was placed by with a blueprint in your cursor. Blueprints in the library are magic, mods can't access them and they don't appear to be in your cursor when you use them. It's very irritating. The foolproof way around it, to wait until the next tick to see if a matching radio body was built next to the I/O port, takes a lot of overhead.