Yes—tripod-mounted setups can still vibrate, and the effect is exaggerated at very long focal lengths. A few things can help:

• Add weight to the tripod. Hanging a sandbag or other weight from the tripod can improve stability. A DIY bag with stones, rice, or similar material works too.
• Keep the tripod as compact as possible. Extend the legs less if you can.
• Avoid touching the camera during exposure. Use a remote release or the camera’s self-timer.
• If available, use live view or any method that reduces internal camera vibration.
• Shield the lens from wind. At extreme focal lengths, wind on the lens itself can cause blur, so stand to block the wind or shoot from a more sheltered position.

At these focal lengths, some movement is normal, so technique matters a lot. Extra support, less tripod extension, no hands on the camera during exposure, and wind protection are the main fixes.