Why is transaction broadcasting sometimes very slow?

Greetings,

I've been trading on uniswap and every once in a while my transactions take multiple minutes to 'get picked up'. It seems like the gwei price doesn't even matter. More often than not the price changes and the transaction will revert. I'm left wondering if node propagation could really take this long.

Example of my last trade:
19:00:00 Submit Transaction with metamask (high gwei)
19:02:00 Finally 'picked up' and visible on etherscan
19:02:20 Transaction confirmed

So even with a confirmation time of 20 seconds the transaction still takes over 2 minutes. Why does this happen and is there any way to speed it up?