I just replaced my rear wheel with a road tubeless (Bontrager RL TLR). Was lucky to have the bike shop installed the tyre, took two blokes to put it on the rim. Anyway, my second ride was a couple of days after I bought it and I can feel the wheel bumped a gap on the driveway. So I went back and put some more air to 90 psi.
Two days after I pumped the tyre, I checked the tyre before riding and it only had 40 psi. Is that normal for road tubeless? I only have to add air once a week with none tubeless tyre.
Follow up
I went back to the shop and they said they put enough sealant and insisted that rapid air loss is normal for tubeless. They also offered to put tube in it if it's too much a pain. Caveat, I asked how others' experience with road tubeless and they said I'm the only one with tubeless. I did see there's a stack of TLR rim strip, presumably from new Trek bikes they sold that came with Bontrager TLR wheels.
I sent a link to this question to them and trek, no response yet.
For now, I will just pump the tyres before every ride.
Edit
To clarify, my question is only about road tubeless tyres relative to road clincher, so they're both "high pressure" tyres. I actually ran the tubeless with less air (90 psi) compared to my front clincher tyre (100 psi). The reason for that was because the tubeless rim is a "wide rim" than (then) usual road wheels.
In case anyone's interested, I only have tubeless wheels now and run them with tubes because 1) losing air was too much trouble and 2) I don't think I can put on a tubeless tyre myself.