Monterey 12.7.6 update appears to shut down my MBP 15

After update to Monterey 12.7.6 , my Mid 2015 MacBookPro 15" now shuts down repeatedly after some 5-10 minutes.. screen goes black/grey and hard restart will be required. Never seen this before. Whilst getting old, the Pro is in good shape having changed screen etc not long ago.. Any known issue causing this ? ideas? Thanks!