Ratchet discovers Bumblebee's Ground Bridge destination with the help of its control panel, while the bridge is turned off. However no one turned it off in the previous scene, and he could have followed Bumblebee himself to learn where he was headed. Instead, the editing makes it seem like he deactivated the bridge for unclear reasons, then turned it back on just in time for Bumblebee to return.
The cord connecting Bumblebee's head to Megatron's seemingly detached itself between shots.
Telescopes the size of the one mentioned do not use lenses, but mirrors.
When Bumblebee leans forward to talk to Raf, the armor plating on his shin phases into his foot.