Page cache makes author location block to disappear

I have an issue where if I have page cacheing enabled, the author location block does not appear. Disable the page cache and the block appears.

My suspicion is that the block simply needs to have a caching option set in gmap_location_block(), e.g. BLOCK_CACHE_PER_PAGE, but my tinkering with that hasn't fixed the problem. For example, setting the block to BLOCK_NO_CACHE, the block will appear for authenticated users with page caching on, but only if block caching is off.

Anyone else experiencing this? Any thoughts on the issue?