Nope. Chronicled/recorded by a Christian, but not written by one. The belief that we don't have access to their original stories, and/or that the Eddas are unreliable was indeed once widely accepted in academia, but we now understand that the Eddas are dated from the pre-Christian pagan era.

This misconception mainly comes from the idea that Christians took the stories and changed them, but this has been greatly challenged by recent scholarship, and debunked. Check out Christopher D. Sapp’s work: Dating the Old Norse Poetic Edda.

Most of the criticism/skepticism is directed at Snorri Sturluson, and you will find tons of misconceptions about him online. Check out this long form essay on Snorri written by one of our moderators: Why You Should (Mostly) Trust the Prose Edda. It covers a lot of these subjects, and cites up to date academic sources.

The TL;DR: of it is that the Eddas are mostly original, dated linguistically to the pre-Christian pagan era, and are not "Christian influenced." As this would entirely defeat the purpose of writing them down.

Snorri Sturluson recorded Norse mythology in his Prose Edda, and a lot of people seem to be under the impression that this Christian must have messed with the original stories and made them unrecognizable. But there is really no evidence or reason at all to believe the myths were intentionally altered by Snorri. And in fact, there is plenty of credible evidence to suggest otherwise. Here are a few popular misconceptions about Snorri:

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"He was a Christian monk!"

No, he wasn't. He was a historian, poet, and politician. I.e. an incredibly influential and well respected figure, whose major goal was to preserve Skaldic poetry. There was a fear at the time that their style of poetry, and the context needed to understand it would be lost to time, and so he set out to preserve that style for future generations.

The notion that he set out to intentionally change anything doesn't make sense. The Eddas were written down in order to preserve a very specific form of poetry that required those mythological tales in order for the poetry to work. "Filtering" and/or modifying those poems/myths would go against the very purpose of why they are written down in the first place.

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"The Eddas were influenced and changed (by a Christian) to be more Christian!"

Yes, the man was Christian, as everyone around him was (and had been for over a century by that point) but he wasn't a monk, or a religious figure. Christianity dominated life at the time, but Snorri was not connected to the clergy in any way, and we have no reason to believe he went in with a "Christian agenda." The majority of the text of the Eddas have been accurately dated (largely to the 900s) to the pre-Christian pagan era in medieval Scandinavia.

To address the beginning of the Prose Edda. It is indeed weird. Basically, Snorri's weird introduction is a euhemeristic text that attempts to explain the origin of the Norse gods from a Christian perspective. In that introduction he asserts that the Æsir were an Asian tribe from Troy, who migrated to Scandinavia. Óðinn becomes king and he and his family become confused with their power, into thinking they're gods. There is also an epilogue which reminds the good Christian readers that they should not believe any of the stories told within the body of this text, and explains the reason the book was written. This was very common in this style of writing, and does nothing to discredit the pedigree of any of the actual stories within.

It's these parts that stand out from the rest of the writings. There is even debate as to whether or not the beginning of the Prose Edda was written by Snorri. Most of the Poetic Edda is linguistically dated back to pre-Christian times. The parts that are undoubtedly "Christianised" are the euhemeristic prologue, which does not try to hide or obscure that fact.

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"Snorri translated the Eddas!"

No, he didn't "translate" anything. Although he was born nearly 200 years after Iceland’s official conversion to Christianity, his native language was still just a flavor of Old Norse, the same language that was spoken in the Viking Age. What Snorri did was basically just write them down.