Yes. The PCR state after booting won't match that of the regular system, so the TPM will refuse to give up the key.

This is contingent on the sealing policy including PCRs that would change as a result of booting a different operating system, like PCR 11, which, when booting a UKI, contains those measurements. Only sealing against PCR 7 would allow this attack, since the default platform secure boot policy would not need to change.