I tend to think you're right. Less than 1 psi per day from a relatively small volume tire isn't much air. However, if it doesn't get worse, I can live with it until this 888 is worn out. Probably be done by the end of the year.
Well, I think I have uncovered most of my tire pressure issues.
I was checking the rear pressure and I seemed to have a hard time getting the gauge to seal on the valve stem. Then I felt some air on my thumb that seemed to be coming from the base of the stem. I then wiggled it and it moved side to side letting air escape each direction. That may be part of why I lost air on my trip. I can see hard bumps possibly jiggling the loose stem and letting small bursts of air.
I've never had an issue before with the Kurvey Girl stubby metal valves. I believe they are double nutted on the inside, but apparently this one worked loose. Fortunately, I have a 50% tread tire on my spare rear wheel that will easily get us to CCR and back. And probably to BWOM-10 at Tail of the Dragon in June.
As for the front, I spent some quality time today slowing spinning the wheel and spraying it with soapy water and carefully watching for bubbles. Never found a single hint of leakage. Decided to spin the tire and check the rim for dents or bead damage. Again nothing. I then lowered the floor jack to raise the rear wheel to change it as mentioned already. When I came back to the front I decided I might as well wipe down the front wheel since it was well covered in soapy water. As I spun the wheel it stopped abruptly. I pulled and it began to rotate, but again stopped quickly. I noted the spot and did it again and it stopped at the same spot. I had serendipitously lowered the front to where the front tire cleared the slab except at the high spot in the tire. A closer look showed a pronounced bulge just off-center in the tread. See attached pictures.
Then, as the now pretty clean tire dried, I noticed another dimple in the tread. I think it is hardware, but it may be a cactus thorn from my desert trip. I can't detect any leak, but it certainly is not to be ignored. So, a new tire is on the way. So, I will have a new front shoe for CCR.