Having a problem with Shivering Isles,

Well here's the deal, my main character who I played through the whole main quest, has no problem with starting Shivering Isles. I rest 24 hours the Quest pops up, there portal is where its supposed to be

However, the SI won't start with my other save ( 2nd character am playing with), and am trying to find out what can possibly cause this. The only issue here I suspect is may be because I have started this 2nd character using ''Alternate Start Revamp mod by Dung Beetle'', and this char never started in jail, hence never touched the main quest. Could this be the possible issue why this character cant start Shivering Isles, when my other save can? I've tried everything, rested an excessive amount of hours, swam around the bay to see if the portal is there etc. with no luck. when i load my other character's save and rest I get the quest!
any ideas ??