Could you provide an online link to the page, as i don't see really about where you have i tags for time?
In all cases, there's nothing wrong to use the <i> tags here, as it is not a semantic content, but just for styling, and by history, i tag was for italic, and the same for b tag for bold. But today, a lot of different interpration about their usage, and not a real clear definition about its usage...
As here, there's no need to emphasize a word or passage of text, the i tag has no issue for example with a screen reader.
Checker are not "human" controller, and <i> does not give issues with browsers nor screen reader, which is the most important fact
But i tag are not banned, just it's recommended to use em for semantic content (not the case here) or a css class instead (eg. using a span tag with a specific class to set font to italic).
In all cases, as i see it is in the list view, with the auto introtext "short description", you have just to change your setting for option "HTML Filtering" and set it to no HTML or custom list of HTML tags
This option is in global options of component > General settings > Miscellaneous
Latest version : 3.7.9
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