What do you expect him to say? "Hey guys, we didn't label one of the images correctly resulting in a black screen at one point that we don't want to spoil. That's fixed now. However, we still can't get a different scene to trigger correctly but we can't give you details as we don't want to spoil too much."
Bugfixing is seriously boring and can be rather time consuming and frustrating. It's done when no more bugs are beeing encountered, you can't put a more conctrete ETA on that than a couple of days.
Yeah, bugfixing is honestly one of the more time consuming (and frustrating) portions of software development. First of all you'd have to basically try to break the software by doing both expected and unexpected user interactions (e.g. clicking randomly), and if you do find them then you'd have to document all the steps to replicate the behavior.
Then, you'd have to categorize and prioritize bugs as critical/breaking, medium, minor (or however you break it down that makes sense as a dev). After that, you'd have to create the fixes, then start the entire testing process again to ensure nothing
else breaks directly or indirectly due to the bugfix solution - a process called regression testing.
I do feel like ICSTOR could be a little more transparent in the testing process - I understand that some bugs are too revealing of the actual context of the game (like some decision pathway breaks the game) - but at the very least post a concrete number of bugs sorted by criticality and their expected resolution time. That's usually how it works in software development, you got a board where you put up your task and have an estimated time to finish up the process. Doesn't have to be detailed to not spoil anything in terms of story, just a general idea of the workload the team has to do in order to ship a working, complete version.