3 Tuya-type devices showing offline but work fine

Hi all. Last week we were visiting relatives and Mrs. Penguin used Alexa to turn on a light and it was very fast. She asked why ours wasn’t that fast. I looked, and it was an Amazon plug, so no kidding it’s fast. We got home and I thought about it. 2 of our most-used lamps are on Tuya-type plugs. So Alexa talks to Home Assistant who calls the Tuya cloud service. Yeah, it’s gonna be slower.
I recently switched my Sonoffs from Tasmota to ESPHome, and 2 Shellys so I decide it’s way past time to flash these to ESPHome. Sd I try to disassemble one. Oh boy, not gonna be pretty. So I re-investigated Tuya-Convert. Oh yeah, it’s Linux, and needs Wi-FI. All my Linux systems are VMs with no WiFi. Then I remember that’s why I haven’t done it yet. I really don’t feel like installing Linux on one of my laptops. Then it hits me. I’m an idiot! I have 2 Pi 3Bs and a Pi Zero. Wow…
So now all 3 Tuyas are ESPHome. They work great, but for some reason, they show offline in ESPHome, even though they work, and clicking logs opens and works. Not a big deal, but is there any reason this might be happening?

Usually Mdns not working.

Thanks for the reply. Using real DNS. All devices have domain: .mydomain.com in the config, and my local DNS is solid.
When I click on logs, it uses my local DNS and works fine:

INFO Reading configuration /config/esphome/tuya2.yaml…
INFO Starting log output from tuya2.mydomain.com using esphome API
INFO Connecting to tuya2.mydomain.com:6053 (10.1.36.115)
INFO Successfully connected to tuya2.mydomain.com

Discovery is based on MDNS not DNS. Check that IGMP snooping is enabled on your network

Well, the other ESPHome devices all show up, it was just the new Tuyas.
Oddly, today they seem to be working. Nothing changed. Weird.