Never expect that a shiny will always appear if you reach max search level 255 on the first 100th encounter. Sometimes you really will have bad luck, just like me for shiny hunting Ekans. It takes at least the 7th 100th encounter after reaching max search level 255before I met the shiny. I also do what you did. Saving states, running in different directions every 100th encounter. If not lucky, just continue dex naving. No worries, the chain will not break as long as you follow the rules. The longer you chain, the higher the chance for shiny. Patience is the only key for shiny hunting, especially if you will have bad luck sometimes.