Imperial Assignments not appearing

In short, stock piling helps with the imperial quests going forward. When you complete a quest, the next one may ask for an item that you have already stocked. So, in general, you will likely get paid back for those items you paid credits to generate. That said, you will do better in the long run building floors that generate credits as a means to make credits. And, if you are diverting too many credits to your inventory you will make less money over time.

In answer to the other portion of your question, many of the lesser items will re-appear in later quests, just in large quantities.

It is a bug, and has nothing to do with your system.

The first 2014 Android update to Tiny Death Star introduced a myriad of problems and bugs, including, but not limited to:

1. defaulting all custom settings.
2. refusing to set any custom settings; therefore:
   1. asking you to set notifications every application start
   2. asking your to connect to Facebook every application start
3. forcing you into perpetual tutorial mode; therefore:
   1. locking you out of completing Imperial Tasks
   2. locking you out of Salvage Droid missions
4. not resolving the "no Retail Value greater than 8 on Android" bug.

As of the time of this answer posting, there has not been an update to resolve these issues.

When I asked Disney Mobile Support (support@disneymobile.com) about this issue they responded in late March with the following email:

Hi,

The developers are aware of the issue and a solution is being looked into. In the meantime, to help us with the investigation, please include the following details in your reply:

Player ID (MENU > Wrench icon > HELP - User ID is the 32 digit long code that you can screenshot and email it to us vs typing it all out)

If any new levels were purchased, how many:

Version number of app installed/downloaded:

From which app store did you purchase/download the app:

Was the app purchased/downloaded/updated via 3G/4G or Wi-Fi:

Was the app installed onto internal memory or an SD card:

Brand name and specific model of your device (Android - About Phone>System Settings or Apple - Settings>General>About>Model):

Device operating system version, language and region settings:

Has your device been modified or rooted from its original manufacturer's specs:

The exact level and/or location where the issue is occurring (please indicate if the occurrence is random):

Are alerts or notifications from other apps on your device popping up during gameplay? If so, please indicate the app(s):

We don't have an ETA for a fix, however, once one is found, an update will be posted in your app store that you can download and use. All updates will contain a quick message about what is included (bug fixes, added content, etc) in the update. We thank you for your patience while we investigate this bug for all of our guests.

Thanks!

Star Wars: Tiny Death Star Support

Feel free to write to them yourself.