It is there now.
I suspect that that you were just hit with a bad timing, as buildbot was then uploading an updated version of the package (after first deleting the old one). Openssl got two bugs fixed two days ago, so a new version has been automatically compiled.
22.03.4 shares the vanilla packages with the ongoing 22.03 branch, so even release packages can disappear from the download server.
There seems to be a problem with the buildbot or download site, so that some buildbot workers take a lot of time in uploading the new packages to the download server.
Last x86-64 build took over 12 hours for uploading. (So there might have been 12 hours of "missing package" from deletion to the upload of the new one)
See the upload step in https://buildbot.openwrt.org/openwrt-22.03/packages/#/builders/32/builds/313
Older mention of that problem: