Hi Deanna - yes, the psyllium can cause this type of bread to get a bit gummy inside. May I ask which brand you are using? I think that can make a difference, but I've only used NOW brand, and I know that Maria Emmerich uses the Jay Robb, so that right there might be one cause. If you are using a different brand, you might cut back just a wee bit on the powder in the recipe.
The other is, as you rightly suspected and tried, the baking time increase. I've tried two things, first, baking longer, or leaving them in after turning oven off, until cooled. That helped.
Also, I sometimes slice them open, either like you would a roll, but more often I slice thin slices - like you would a loaf of bread, tiny little slices, and just let them "dry out" on the cutting board. We mostly use them for our pate, so that is a perfect bite size piece for us.
They also seem less gummy if sliced after cooling.
I hope that helps, you could also toast the rolls, after slicing, that would definitely make them less gummy.
But I'm glad you and your hubby enjoyed the taste - they have really been nice to have for that once a week treat for the GS to have some liver pate - I delight in his lip smacking and exclamations of
"dats so good, Mimi!!"