Fan and Light Switch Reversed
There may be a problem depending on the model you have the s2-lf-wh model 300w on the dimmer it was not clear if they used a different type of control on the 2 sides it just stated 300w 2.5amps. The other models s2-lfsq-wh show single pole 300w for the fan and 150w for the light on this model it may damage the electronics if hooked up backwards. With most electronic controllers a flash can be a bad thing so I would want to correct the issue just in case so your nice new switch keeps working for years.