Strange password prompt during install

i’m in the process of reinstalling the base mojave operating system on a 2018 macbook pro. during this process, i was prompted to and successfully entered the encrypted ssd password. once the install started, it was interrupted by an odd looking dialog that was again asking for the ‘disk password’ however, the ui, font and coloration did not look like apple’s macos design. what i found to be odd: title text didn’t look like macos fonts characters that hid the password were square (instead of round), and the color was a light turquoise. this color was over a white entry field and readability was difficult the cursor arrow was also a light turquoise and was bound within a black box has anyone one encountered something similar?