No redness after IPL treatment. Was this supposed to happen?

Thanks for you question, but why were you being treated?  The 2 primary reason for IPL PhotoFacial would be to treat brown pigment or broken blood vessels (vascular lesions).  If they were primarily treating vascular issues, you really wouldn't be red afterwards.  If they were targeting brown pigment, we would expect those spots to become darker.  They would eventually come to the surface and flake off.  We do not ever expect any large areas of scabbing or flaking.Next question, where did you get it done?  Was it done in a medical office with an American made devices that has been serviced recently or was it done in a med spa with a cheap box from China?  An IPL PhotoFacial treatment should be mildly uncomfortable, but not painful.  Much of your results are dependent on the overall power of the device, maintenance of it, the settings used and the technique of the provider.  Unfortunately, you really do get what you pay for.  I hope this helps.

IPL or BBL will not always cause downtime and when the main objective is to prevent aging of the skin then a lighter treatment is all that is needed. 
The forever young study looking at using BBL twice a year for nine years showed 1200 different genes turned on that were associated with a more youthful skin profile. The patients in that study were judged to look 2 years younger than when they started or 11 years younger than they were at the end of the study. These patients were not getting an aggressive treatment causing peeling, burns, flaking or even redness. They did receive a larger number of flashes over the face than the typical IPL. 
Outside of BBL being a superior technology that delivers the same amount of energy at a lesser intensity and more focused into the target, it is also used differently than what most laser practitioners do with an IPL device. With BBL you prep the skin with two full passes over the face, then you go back with smaller spot size adaptors and different filters to target specific problems areas. In one BBL treatment I may use 240-300 flashes over the face versus the typical IPL where there may be 50 very intense flashes. In the end, patients’ skin will look less irritated after the BBL session because we are letting the technology do the work rather than trying to crank up the energy on an IPL device, which is what produces a sun burn appearance after the treatment. 
When I treat someone for Rosacea  they will appear more red for a day or two after. With hyperpigmentation, the areas will become darker for about a week and then flake off. If these were the concerns you wanted treated then these are clinical endpoints that can be a good index of the treatment’s efficacy. 
It is possible to have too weak of a treatment and this still could be the case. You should discuss this with your laser practitioner but I would suggest that you look into a BBL treatment to get an idea of what the difference is for your specific condition.