INSTAGRAM temporarily blocked a key feature on Wednesday after it appeared to favour Donald Trump.
Related hashtags, which appear in search results, displayed negative related hashtags for US presidential candidate Joe Biden, but hid them for Trump.
Instagram blamed the error on a "bug" and said it had disabled the feature while it worked on a fix.
"A technical error caused a number of hashtags to not show related hashtags," Instagram told Buzzfeed News.
"We've disabled this feature while we investigate."
Related hashtags appear above search results for other hashtags. A search for #ChristianoRonaldo, for instance, may suggest #Football, or #LeoMessi.
The feature algorithmically pushes people towards related content they might like, but for at least two months it wasn't working properly.
A Buzzfeed investigation found that related hashtags for searches of Joe Biden included phrases like #trump2020 and #neverbiden.
Because many of Biden's hashtags were derogatory, concerns were raised that Instagram was favouring Trump.
Instagram said the bug prevented related hashtags did not appear on the tens of thousands of hashtag pages.
It's not clear what the source of the problem was or why it only affected certain hashtags.
By pointing the finger at a bug, Instagram suggested the issue was not fuelled by political bias.
The problem is likely to reignite the debate surrounding the role of social media companies in the upcoming US presidential election.
An outraged Trump roasted Twitter in May for labelling his tweets with "fact-checks" for the first time after he posted about "rigged" mail-in votes.
He fumed that the social networking service was "interfering in the 2020 Presidential Election" and said he would not tolerate it.
Last month, Facebook flagged a Trump post warning of a "corrupt election" by re-directing users to "official voting info."
Experts have blasted Facebook and Twitter for allowing Russia to carry out a “sophisticated” hijacking campaign during the US election in 2016.
Instagram – the key facts
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