That's what the notification email is stating:

augenauf ran a test of 2.6.75-300.fc27.x86_64 (PASS)
    https://apps.fedoraproject.org/kerneltest/kernel/2.6.75-300.fc27.x86_64

uname -r says: 4.15.14-300.fc27.x86_64

Do you have logs for the 2.6.75 kernel under kernel-tests/logs?

No, I mean I haven't touched 2.6.x in many years if not decades. Though, when I open the log file it says:

Date: Mo 2. Apr 10:18:59 EDT 2018
Test set: default
Kernel: 2.6.75-300.fc27.x86_64
Release: Fedora release 27 (Twenty Seven)
Result: PASS
Failed Tests: None
Warned Tests: None

Somehow it got detected as 2.6.75. The suspicious log can be found here: https://paste.fedoraproject.org/paste/3hVgaDlmd34gTBu0uKHjUA

In the meantime, I just re-tested (after a reboot) and all works just fine.

Haha, I would hope not, but people do all sorts of fun/weird things. It's conceivable that one is into old kernels.

That is really bizarre, though. The runtests.sh code isn't doing anything weird to get the kernel version. It sets kver=$(uname -r) on line 24 and down on line 118 it runs echo "Kernel: $kver" >> $logfile to cram it in the log. The only other time the kver variable is touched between setting it and putting it in the log file is on line 49 to check to see if tests have already been run for that kernel version.

I'd be really interested if you're able to reproduce this, but otherwise this issue should be closed.

I am not able to reproduce this. I have run two more tests and all is fine.

I looked up the history of the 2.6 kernels. Interestingly, there was never a 2.6.75 kernel, after 2.6.39, they released 3.0.

I confused by what's going on here - but let's close the ticket for now. I'll get back if something like this happens ever again.