I've just discovered and installed the plugin as I have a perfect use case for it in one of our sub-categories ('Places to Go'). I've retrospectively gone back over about 20 topics and added a geo-location with the plug-in. It's working fine with the mini-map but when I view the category map I only see six pins.
I'm running Discourse 3.4.0.beta4-dev ( d1b3b85584 ) and I'm using the default provider (nominatim).
I haven't found anything to point me in the right direction in this topic yet but I may have missied something - it's quite long. Could it be related to the number of requests being sent to nominatim? I'm still getting to grips with the way the plug-in works and continuing to try and figure it out in the meantime. I plan to look at the benefits of other, paid, providers and whatever else I can think of to tease out some hints or an actual solution.
Thanks for any advice and thanks for sterling work maintaining the Locations plug-in, @merefield.
Oh, and Happy New Year (just under an hour away here)