1.- Activate Twenty Fourteen on a test site (It also happens on some other themes)
2.- Add the Twitter Timeline Widget
3.- Add parmafansww as the username
4.- Check the site on an iPhone (Checked with iPhone 5/ SE and 7)
Tweets in the timeline to be correctly displayed

Tweets in the timeline are wider than the widget DIV

(In this image I added 2 Twitter widgets, one for the above mentioned user and another one for mine rantoncuadrado -that is working properly-.
Screenshots
If applicable, add screenshots to help explain your problem.
A CSS fix was proposed in p9cu9o-1xJ-p2 but it doesn't really fix the problem:
@media (max-width: 600px){
.content-sidebar iframe#twitter-widget-0,
.content-sidebar > *,
a#clustrmaps-widget-v2,
#clustrmaps-widget-v2 > *,
.clustrmaps-map-container > * {
    width: auto !important;Â
}Â Â Â
.site {Â
       overflow-x: hidden;   Â
}
}
The overflow-x: hidden; doesn’t necessarily fix the issue but at least doesn’t show that bar anymore.
I used 2 twiter timelines mine and user’s to be sure it has to do with the particular picture they have. And it seems so (Mine rantoncuadrado is the first twitter timeline, user’s the 2nd)

After applying the CSS code both timelines are impacted

Note You can’t reproduce the weird behavior in a computer even with http://quirktools.com/screenfly/ or so. You can just see the bug on a real iPhone
Test2: Has it to do with a given tweet?
The tweet that seems to be causing the issue is the t-shirt retweet… Well, I also retweeted it on my Twitter account, but cannot reproduce the problem. It is still properly displayed on my profile, but not so in the user’s

Test3: Is it browser related?
Browsers behavior (iPhone 7):
Chrome, Safari, Opera Mini and Brave: same issue
Puffin: WORKS PROPERLY!
Firefox: Doesn’t show the tweets (?)
Puffin picture:

Test4: Is it theme related? It doesn't seem so.
I changed the theme to Apostrophe2 and the issue is still there on iPhone… well it is even worse. In Firefox the Widget is not showing the time line at all, in Chrome, this is what we get:
I am experiencing a similar issue. The debugging I have done so far has not produced any leads.
Can be viewed on this site.
Also facing this issue, and seemingly managing for now with the following CSS
.twitter-timeline {
width: 100vw !important;
}
Looks like this issue isn't resolved 14633184-hc
@jeherve Any news on this?
Can confirm that Darrin's CSS worked
Another report of this here 13693797-hc
Gave them CSS fix in the meantime
Any news on this?
Not yet, but we'll update this issue when we start working on this.
This bug affects iOS Safari in general, not just iPhones, and is a longstanding issue.
This solution worked for me. For reference, you assign to the iframe a min-width: 100% !important and a width:10px !important (or something that is less than 100%).
The AMP project solved this issue in basically the same way: https://github.com/ampproject/amphtml/issues/11133
116927-hc
Provided CSS workaround.
I couldn't reproduce this issue on mobile (both Chrome and Safari) on iPhone XS and iPhone 7.
cc: @rantoncuadrado
This issue has been marked as stale. This happened because:
No further action is needed. But it's worth checking if this ticket has clear reproduction steps and it is still reproducible. Feel free to close this issue if you think it's not valid anymore — if you do, please add a brief explanation.