Arbitrage in cryptocurrency trading is quite a risky business. You have to take into account delays in transferring coins, accidental account freezing, sharp price changes, interest on trade volume, and many other factors. mistakes can lead to loss of all profits created by hard work
this is very much true, even in dex there are several factors that could leads to arbitrage loss like when smart contract of certain token suddenly changing and many more.
arbitrage isn't as easy as it seemed because there are many complexities behind the scenes and I think the core of having succesfull arbitration is through anticipating all these mistakes which sometimes we don't even know if we've made some mistake.
usually the thing that makes most arbitration failed is definitely the sharp price changes in which occurred quite frequently, remember that we are not the only one that lives in this planet and also have brain, others have too and most certainly they also gonna make some arbitration if they have the sufficient capital in their hands so of course if they are faster in taking action the other will incur loss in which usually quite massive.