An update to the Just Cause blog announces a patch is coming for Just Cause 3 this week updating Avalanche's action sequel to version 1.02 (thanks Shok). They specify the PC patch is coming Friday, and address some player concerns not covered by the patch, along with an outline of what sort of changes to expect:

Since launch, we’ve been pouring through your reviews and comments to help us prioritise our fixes accordingly. We know many of you have been patiently awaiting today’s patch, and this update is part of a much larger plan to optimize and improve the game. Thanks for your patience here.

In the 1.02 patch (132.1MB), you can expect:
+ Significantly improved loading times
+ Optimizations to online stats
+ General stability fixes
+ Fixed an issue related to challenges, wherein vehicles sometimes disappeared when starting a challenge
+ Fixed issues related to screen resizing and closing the game window before the game has fully started up [PC ONLY]
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To those of you still having issues, rest assured we are working hard to alleviate these, and are listening very closely to everything that’s being said.