That is in the normal range for XEC/DGB. The time a swap takes is set mostly by the block spacing of the two chains involved, so a pair with slow blocks is slow for everyone, every time.
The swap stopped at NegotiateFailed. The two sides could not agree terms, so the swap stopped before any payment.
taker_swap:1222] "lp_swap:438] Timeout (219 > 180)"
Recorded by the swap's own protocol log, which is the only source that knows: the aggregator reports failed and completed swaps identically. Nothing changed hands, so it sets no reference price.
Only completed swaps are checked against a chain, because the check asks whether the agreed trade actually settled. This one did not complete, so there is nothing of that kind to confirm.
Reported by kdf-statsdb.