I would agree with spahappy and chas, it's probably something simple and has to do with the electrical hookup.
Hotspring and Tiger River have a unique wiring setup to anything most electricians are used to.
For all of the years I dealt with them I found more problems with electricians trying to do it their own way and not following the schematic.
One of the most common problems is the main breaker in the house not covering 2 legs of the 220 so that it looks right, you have 110 power on each line but do not have 220 between them and the spa is jumped for 220 but running on 110. This is as easy as just repositioning the breaker in the box.
Please keep us posted on what they found.