Combine does vertical leap not max vertical reach from standstill or with approach
Here are the top 5 guys at the combine in max and standing vert.
Standing Vertical Leap
1.   Donte DiVincenzo   34.50
2.   Trevon Duval   34.00
3.   Gary Trent   33.50
4.   Josh Okogie   33.00
4.   Zhaire Smith   33.00
Max Vertical Leap
1.   Donte DiVincenzo   42.00
1.   Josh Okogie   42.00
3.   Trevon Duval   41.50
3.   Anfernee Simons   41.50
3.   Zhaire Smith
You can draw more accurate conclusions, at least free from any potential bias, by adding their respective jumping totals to their standing reach measurements.
For perspective,  Udoka Azubuike measured in with a standing reach of 9' 4.5'' and had a standing vertical of 31 inches. That's approximately 12 feet reach off a standing leap. So I would think it's fair to say he would likely beat Williams' alleged Mark if he were running.
Bamba had Azubuike by 3 inches in standing by reach, but didn't partake in any jumping drills. But with that reach he wouldn't have to jump too high to eclipse Williams either.