I am running a Joomla v3.3.6 website with K2 v2.6.8.

I have setup the website for K2 Frontend Edit functionality, which mostly works correctly without issue.

For a few of the K2 Categories, some of the associated Extra Fields are type 'date'. Specifically for these 'date' Extra Fields, the Calendar popup does not initialize, strictly for the Frontend. If editing, from the Backend (Administrator) they popup and function correctly. I require that the Frontend Calendar popup function for the editors of the website.

I checked for errors/notifications (browser), which there were none.

Worth mentioning, is that this website is using a custom made template. When creating the template I made sure to follow the Joomla docs, however it could be I overlooked/missed a critical step. To my knowledge there are no other potential template related issues at this time.

Any help/assistance would be greatly appreciated. If I can provide more info or details, just let me know. I will update with any new progress.

It could be a JavaScript issue or a CSS issue.
If your browser's console tab is not showing any errors,
check the DOM to see if the element is indeed there and is not shown due to a CSS z-index or positioning issue.

I have verified that within the DOM, the element it actually there.

Then it is a CSS issue in your overrides if the element does not have an inline style of display: block.