YouTube confirmed Monday that it is not showing "some videos" highlighting LGBTQ issues for users who have opted in to the platform's "Restricted Mode."

Many prominent LGBTQ vloggers and voices took to Twitter over the weekend using #YouTubeIsOverParty and #YouTubeRestricted to highlight concerns that their content was missing or blocked when Restricted Mode is switched on.

Among the content still hidden early Monday in that scenario was a video of a lesbian couple's wedding and a vlog highlighting eight black LGBTQ trailblazers.

Responding to questions about those two videos, a YouTube spokesman told NBC News via email Monday that “some videos that cover subjects like health, politics and sexuality may not appear for users and institutions” that choose to use Restricted Mode.

.@YTCreators you're blocking everything with any hint of lgbtq+! Vids of me swearing aren't restricted but transwomen makeup tutorials are — dodie (@doddleoddle) March 20, 2017

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Users can opt in to Restricted Mode in order to “screen out potentially objectionable content,” according to YouTube owner, Google.

A description in its privacy and security settings states: “We use community flagging, age-restrictions, and other signals to identify and filter out potentially inappropriate content.”

A tweet sent from the YouTube Creators account late Sunday stated: “We are so proud to represent LGBTQ+ voices on our platform — they’re a key part of what YouTube is all about. The intention of Restricted Mode is to filter out mature content for the tiny subset of our users who want a more limited experience.

“LGBTQ+ videos are available in Restricted Mode, but videos that discuss more sensitive issues may not be,” the statement read.

The YouTube spokesman said that a "very small subset of users" had switched on the feature.

Vlogger Rowan Ellis, who has more than 22,000 followers and describes the content she creates as “pop culture from a feminist and queer perspective,” posted a ">video Friday in which she stated that around 40 of her videos cannot be seen on restricted mode.

“We don’t really know how long … it’s been there but it’s something I think people are just starting to realize the extent of it, particularly in regards to LGBT-related content,” Ellis said.

Others posted examples on Twitter in which it appeared that videos with titles that included the words “gay” and “lesbian” were hidden in restricted mode.

Just looked at my videos with the "restricted mode" on. Seeing a bit of a theme here...



LGBT+ content not safe for kids @YouTube? pic.twitter.com/KnhayE4h1y — fiona (@neonfiona) March 16, 2017

Users who specialize in virtual reality and gaming videos, meanwhile, also reported that some of their content appeared to be blocked, appearing to show that the issue was not restricted to LGBTQ YouTubers.

A search for LGBTQ-themed videos while using Restricted Mode on Monday morning still brought up 240,000 results including posts entitled "More Americans are Identifying as LGBT Than Ever Before" and "10 Times You Were Proud To Be LGBT in 2015."

My ENTIRE CHANNELS CONTENT is gone under YouTube Restricted mode!!! Please retweet this for awareness. pic.twitter.com/2RKInwDg9y — Gaijin Goombah (@GaijinGoombah) March 15, 2017

WTF @YouTube if restricted mode is on,nearly every vid I am physically in is gone.Only 110 out of 306 videos are visible. I don't even curse pic.twitter.com/sEju9EFRY1 — Heather Feather ASMR (@HeathFeathASMR) March 16, 2017

YouTube and its owner Google have scrambled to prevent the loss of prominent advertisers in recent days who are concerned that their ads are appearing next to extremist content and hate speech.

The U.K. government, L’Oreal, Audi and HSBC have all suspended their promotional material from appearing on Google ads and the video-sharing platform in recent days.