No, they are not showing for several days now.
My adsense is 4-7 years old, maybe even older. I never had any issues for years. And ads were showing for years on these sites from adsense without any issue what so ever.
Yes, I have it on all of my websites, adsense is not showing any ads.txt files missing.
Yes, I can see blank ads on my site.
I have mention this like two months back.
my adsense account is quite long like 5 years old , no issues all along
ads appear using auto ad.
is around this year they seem wanna so call " give more value to ad buyers " i think
you can go adsense support community , there is a tread just search ads disappear etc surely will appear.
you will see they pin Gold member message explain and give support link
according to google is quality traffics. but one thing ironic is a lot publishers got good organic traffics yet also their ads disappear
but after one week or so back again is like on and off situation .
I got monitor those big establish sites yea those for an example like CNN , BBC type of establish companies
their google ads always there.
i feel " maybe " google change some policy , want to safe guard , give ad buyers more value come to buy google ad
so they " maybe " only show ads on those good site with tons of traffics . those average to low traffic site will get hit by these no ad been slow.
this is just my guess.
Google adsense never give an official reply. Only gold members show explain why
one thing i find it surprise, they claim social media traffic is not consider quality traffic , beside email list etc.