What does Amber Gated mean?

It's a traffic-analogy from the OGC Gateway™ Review planning process.

Typically there are gateways (or gates) representing critical requirements, they will be assigned a red, amber or green (RAG) status, representing the severity of issues in achieving that requirement. My workplace (a large one), apparently like the place referred to above, uses such a system for managing the yearly employee review. Completion of training requirements, adherence to regulations, career plan discussion with boss, completion of reviews with staff reporting to you etc. are all gates the employee needs to "pass through" in order the complete the review. To speak informally, to set an employee's status on one of their gateways to red or amber would be to "red-gate" or "amber-gate" that employee. They are blocked from completing the process until the relevant issues have been addressed.

Here's a document discussing it. See p10 for colour coding meaning. Basically red means immediate action required, amber means action required, but not immediately.