Musgrave is definitely the one who ordered that attack on the bridge

The movie never says how Davian's men were able to find him, but I bet it was Musgrave (the mole) who ordered that attack on the bridge.

When he found that Ethan and his crew had captured and grabbed Davian and were heading back, I bet Musgrave was like "Oh fuck no!" and immediately called for backup, lol.

Considering he's a mole, he probably has access to contacting people who work under Davian.