Google ranking issues on reoptimised blog article

Hi all,

I have been for the past 2-3 months reoptimising old blog articles for my companies website. I have seen some good success, with articles that weren't ranking or ranking very poorly jump on to the first page.

My most recent article I posted two weeks ago, and within 4 days I had seen it reach rank 1 and own the featured snippet, but that only lasted a single day and then my keyword tracking tool showed it was no longer ranking (manually checked too). Since then I check every day and sometimes it is not ranking and other times it could be position 76. I know it's only very early days for this contents life span but with all the other articles I've seen great results within a few days and the rankings remain.

The target keyword for the content isn't competitive at all (search volume of 30 and top ranking content isn't that good) and the content for this article is actually very in-depth and long form. I redirected the previous URL to the new one and have made sure there is no internal links to the old URL. Right now the new and the old URL is indexed in Google but I dont think that would be an issue. I also have the same article published across different subdirectories on my domain as we have different subdirectories targeting other languages but hreflang is set up correctly and this should not be an issue as the other articles aren't affected.

Does anyone have any idea or has experienced this jolt of ranking to the top and then taken away quickly and to not even be ranking anymore for a very low competitio keyword?

Thanks