Yes, but in principle it's just a texture or rendering bug, you still get the money and points with 100 people, they just don't show up. But the reason for the bug
You're right - the issue seemed to right itself when I refreshed the browser and could see all the people again with the money going up at a similar rate. Interesting that the people carrying the water seem to synchronise over time even though they should be moving with constant speed relative to one another.
All that aside, a great little game to burn some time! Thanks for publishing!