@lakelander Some cases are due to our current data feed provider. We may get an ask price from a rather illiquid exchange. Nonetheless, rest assured that these prices are not tradeable because the order is always routed to the most liquid exchanges to meet NBBO.
However, looking at IITU & VWRL specifically, I found that these are legitime ask prices on the LSE order book. If you want to secure a specific price, it’d be best to use limit orders.
P.S. We’re switching providers soon so this won’t be happening in a few weeks.