Increased Kinesis latency resulting in low gets and high delays via Lambda

We're using Kinesis as a buffer for Lambda, which then inserts into Redshift. We're seeing very high delays in data coming out Kinesis and we're worried this is resulting in data older than 24 hours being dropped. We currently have 3 shards running, and are no where near our maximum throughput.

The two attached files show the stats from our Kinesis stream. What could be causing this to happen, and how would I go about fixing it?