On January 5 Bitcoin Cash (BCH) recorded a block time of 5.5 hours, meaning that it took 5.5 hours to find the next block. During this time no transactions were confirmed, and this obviously would cause anxiety and stress among anyone who was trying to send a Bitcoin Cash (BCH) transaction at that time.
This is not an isolated incident. In a recent article Crypto.IQ tested out the capabilities of the Edge Wallet via exchanging Bitcoin Cash (BCH) for Bitcoin (BTC), and it took 3 hours and 20 minutes for the Bitcoin Cash (BCH) deposit to get the 3 confirmations necessary to complete the trade.
On average a Bitcoin Cash (BCH) confirmation should only take 10 minutes, so these long block times are highly anomalous. Also, it is likely that there are far more slow block time incidents than the two examples in this article.
The culprit is likely hash rate variability. Since the end of December the Bitcoin Cash (BCH) hash rate has skyrocketed from 2.3 EH/s to 4.1 EH/s, representing a ton of mining rigs being added to the network. If a fraction of these rigs suddenly go offline, i.e. they switch to mining a different cryptocurrency, then anomalously long block times would result.
Bitcoin Cash (BCH) has an emergency difficulty adjustment mechanism to mitigate this sort of situation, but clearly the developers need to re-assess their algorithm, since such slow block times have the potential to decrease adoption by scaring away users.