I wouldn't know if that still compares as "very fast"

Well, it is surely much faster than my 5 years old i5

I have done the following changes to fix the bug:

• The failing code has been conditioned to be executed only when in aerial view mode;
• The critical code has been synchronized;
• The delayed code has been serialized to avoid thread saturation.

You can download it from here: Pan3dView-1.8.sh3p

Please let me know if this fixes the problem, so I'll publish it on the contributions page.

Daniele