I'm updated to the Hotfix 1.6.0.51765 and I noticed the outposts stop working when I create a second one. Tested this in the New Home game when I create an outpost at Tesla city.

I've noticed this too. Dismantling and re-establishing the outpost site seems to fix the issue, at least temporarily.

The current patch is 1.6 Hotfix 3 under the downloads. That didn't fix it. I'll check again when it updates.

Can confirm for new hope. Building two outposts seems to prevent both of them from sending resources. If one is dismantled the other sends its package immediately.

If it is related to multiple outposts, then New Home is perhaps the only places it comes up. Outposts are not allowed in Arks, On the Edge, or Endless, you're only allowed one outpost team at a time in Refugees and Winterhome, and I'm not sure if the teams in Last Autumn work the same way (and there's not much point in having more than one team; on the higher difficulties you can't afford the extra research, on the lower difficulties two teams is overkill).