Bubbles in transmission fluid

My van has 99250 miles on it an Ijust had aselonoid put inside of it an had the fluid changed,but now it has bubbles in the fluid.What causes these bubbles. The fluid was changed about 2 or 3 months ago.

This is usually caused by overfilling of the fluid which then leads to frothing or there’s a problem inside the transmission pan.

The latter could mean that air is being sucked into the transmission valve body somewhere. This could be due to something simple like a transmission filter not being installed correctly. No matter, this needs to be cured before it damages the transmission.

It’s difficult to say because we do not know exactly what was done with the transmission, what the fluid level is, etc.