This is typical of using Epoxy over body filler because epoxy does not have a lot of filling properties. Usually a good 2k primer surfacer is sprayed on top of the filler and then blocked. After final blocking then a seal coat of epoxy is sprayed before color is sprayed. SPI epoxy has enough filling properties that you could spray it and block it but it will take more than one coat.
One word of warning. In most cases your sanded body filler is not going to be level enough for your car to be ready for paint. Since I have not seen your car I have no right to say it isn't but...... I would have doubts.