I believe a few scripters/users have reported this issue (on many scripts, it's a bug in the client) which occurs only on OSBot's lowcpu mode where the client seems to fail to hook rs data for containers (inventory, bank, grand exchange) when they are closed (in your case it's trying to obtain inventory items but the bot is on world list tab), I strongly advise you to run without any special modes unless you are running a goldfarm and you really need the small resource difference until this bug is fixed. It may have been fixed in the .122 dev build but I'm not really sure as it's very hard to reproduce. I've personally noticed this error on pretty much all SDN scripts I tried which include world hopping in the last ~12 months or so including my other script Stealth Quester, where I implemented a "temporary fix" by force opening the container (inventory in this case) and has been working for about a year with only inconvenience being having to randomly switch to inventory tab from time to time. I'll add it in a few hours on the next SDN update to Stealth Builder just in case it won't be fixed by the new client versions, for people who prefer the lowcpu mode.
PS: the script has been updated about 12 hours ago to work on the .122-.125 dev builds, if you encounter this issue (with any OSBot script) on the dev builds or without lowcpu, send me a PM and I'll forward a bug report to the client developers
Just out of curiosity, did you recently login/hop worlds? (recently as in the inventory tab has never been opened since login/hop)