As mentioned by user48956; setting the input width to 100% leads to the disappearance of flags in chrome.
I use bootstrap and often have forms where I want all inputs to stretch 100% and do not want to use bootstrap form methods , and this problem still arises.
If you define input {width:100%} , you can put the width in the div containing this flag and it will be fixed. eg.
<div style="display:inline-block; width:20px"><input type="checkbox" name="read_privacy_policy" id="read_privacy_policy" class="pull-left"></div> <div style="display:inline-block">I have read and understand the Privacy Policy.*</div>
or you can set style="width:auto" to the input itself
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