The OP did not verify whether the story in the comments was the answer, or the similar question linked in the comments answered this one.
I just read it, and it does match.
mentions recalling a short story from Asimov’s sometime in the past 30 years involving:
"Crucifixion Variations" by Lawrence Person is in Asimov's Science Fiction May 1998.
A scientist looks backward and sees the resurrection of Jesus, but then looks again and sees Jesus crucified without any resurrection
Two academic researchers in a top-tier lab do this research on a ten-million dollar no-strings grant from a religious organization.
It's told in the first person by the administrator, who has his doubts about hiring the ex-criminal rabid christian who is still undeniably the best "E-particle" physicist in the world.
The narrator fears emotional instability of someone with such a religious view if the experiment produces results that don't match his religion.
I needed a hard-working drone, not a crusading zealot.
This technology, the further back in time one looked, became less accurate because it might show the past of a parallel timeline as well as the past of our current timeline
There is a description of the signal-to-noise ratio deteriorating, and a reference to observation changing the phenomenon.
... there is no guarantee that the event recorded actually occurred as depicted in the computer simulation. This inability to distinguish between “true” and “false” pasts is both unavoidable and gets worse the closer to the present you get, where the signal-to-noise ratio goes so overwhelmingly negative that no amount of processing power is capable of resolving event waves into a coherent picture. The technical word we use for this noise is “fuzzing,” and once you get past the thirteenth century or so AD, everything is pretty much hopelessly fuzzed out.
According to them, we’ll never be able to resolve an event wave that truly depicts our own past, since any “true” event is altered by its very viewing.
The brilliant zealot accomplishes what turns out to be the "first run" which shows the corpse disappearing in scintillas of light.
He has the joyful reaction one would expect of an extremist.
While at home, the narrator is called to come to the lab immediately. His researcher has done a "second run" that shows a corpse simply staying there normally.
The researcher, as the administrator feared, has come undone by the "no resurrection" result.
The brilliant zealot has drunk the contents of the empty whiskey bottles in the room, has destroyed a computer terminal, and attempts to kill himself with a broken bottle.
Both had their world view shaken to the core. It ends with the conclusion that we can never know which scenario was our actual-event "real" timeline, and the compelling possibility that neither of them was.
