If this is the B9core using the Black resin and the grey resin you need to call or fill out a trouble ticket and submit it immediately or send an email or call your seller about this it is not something we can help you with,
because the B9 Core is not an open source printer like the previous models were and actually no on here can help with this issue unless it is to say
clean and strain your vats, shake or mix your resins well before printing, make sure the vat is allowed to breathe as the clear area needs to be exposed to oxygen after 4 or 5 print sessions.
Plus if you not cleaning your prints well you will have nothing but problems.
Most all of us do not use alcohol to clean the prints we use a mixture of Dawn soap and water in a hot ultrasonic in a container or a plastic baggie.
Oh and make sure you have updated to the most current version of B9Core software.
other than the above recommendations you will need to go to http://www.b9c.com/support/b9-core
and file a trouble ticket.