No, students can use multiple computer devices for CBT test sessions. The student should log out (i.e., submit the test answers or pause the test to log out) before logging into a different computer.
Logging into a paused-student-test-session on a different computer will return the student to the point within the test where the student paused the test. Note that a Proctor PIN is necessary to log a student back into a paused test session.
Multiple students can use the same device during a testing day as long as a student is individually logging in and out (i.e., submitting the test answers or pausing the test to log out) of a test session before a different student uses the same device for a new test session.