'Processing issues' can mean 2 things, Executive Function deficit and/or Weak Central Coherence.
Executive function covers 4 main areas: planning, inhibition, generativity and mental flexibility. Take the example of cooking dinner:
Someone with a planning deficit will struggle to sort out all of the steps necessary and follow them through to completion. They struggle to sort out in their head that they need to shop, decide a menu, prepare the food, lay the table etc. For some they may cope fine with the high level stuff but just have problems following the recipe. Or they may cope with all the steps individually but can't cope with them all together. Others need even simple tasks, like laying the table broken down into much smaller chunks. Eg 1. take the table cloth out of the cupboard, 2. spread it over the table, 3. get out 4 placemats etc
Inhibition deficit would be that they go to do their shopping but get distracted by the cake counter or spend hours reading the magazines. Or go off and loose themselves in something else and forget that the food is in the oven until it's on fire (my daughter is particularly skilled at creating fires this way). Also things like loudly asking questions during the film at the cinema.
Generativity deficit would mean that your mind is blank when thinking about what to make for dinner. You want something different but you just can't come up with anything new. So you have beans on toast. Again. As you do pretty much every night.
Mental flexibility deficit would mean you can't move easily from one task to another. So you would have problems coping with leaving the vegetables half peeled while you check the pie is ok in the oven. And if someone were to knock on your door half way though, your brain might explode.
Weak Central Coherence is where autistic people can see things in much greater detail than others but have problems with seeing the broader picture. I have this problem. Someone else might clean their living room in an hour. They see the broader picture, so clear away the clutter, flick the duster round, quick vac, job done. I am so focused on the detail that I spend that hour dusting the mantle piece and making sure everything is back EXACTLY where it came from. Therefore it takes me 2 days to clean my living room. Alternatively I sometimes can't follow what is happening in a film or book. I can see details that others don't (can't bear it sometimes if the lips are a nanosecond out of sync with the audio) but I have trouble processing the immediate information to create general overview of what is happening.
Does that make sense? (In a waffley aspie way)