Making a memory requires intention and attention. Most people don't remember the drive to work, going to the toilet, or showering, but their way of interpreting the world includes a little summary step, a sort of "Yep, done that" for each task. They remember that they showered, but they don't remember showering. When they then try to recall showering they confabulate something reasonable, a sort of stand in for having a shower, but it isn't recorded that morning, it is just a kind of simulation of what showering is usually like when they have a shower at home, in the morning, on a workday etc.
Because you have fewer executive function slots you are using all of them to do your tasks, so you don't have spare slots to also make summaries. This is actually not a bad thing, I mean who really wants to have full video memory of every shower they have ever had, but it can look like memory issues if you have incorrect expectations. Most people don't remember most of what they say they remember, they remember a summary which compresses it and makes it much easier to store but not a full recollection of the event itself.