It happens, nothing wrong. Supply can sometimes be delayed due to excessive demand. Improve your offers for supplies or be patient. It'll work itself out.
I see that Alyan, I thought I was the only one. Someone else is catching the same grief as my country. I'm just bracing myself for private and enterprise business owners to threaten me with certain death.
If you are a free member, your buying strategy doesn't matter since it automatically buys at "best price". I'm having the same problem right now. There are a few solutions for the free player to solve this.
One option is to just keep an eye on your corps and change any product order which has a shortage to "immediate". You'll end up paying about 20% more for product this way, but you'll get the product.
Another option is to somehow contract those products in high demand. This likely is the most costly, as you'll almost certainly be paying for higher quality. However, you won't have to keep constant vigilance over your supplies this way.
You could also decide to cancel your country and start over on another world. I know GR doesn't have this problem, as I just moved from there. Products on LU nearly all have ridiculously high demand because of the large number of players. "Best price