We are playing Curse of Strahd and we encounter this creature: deva.

It has an Angelic Weapons feature:

The deva's weapon attacks are magical. When the deva hits with any weapon, the weapon deals an extra 4d8 radiant damage (included in the attack).

It also has Change Shape in one of its actions:

The deva magically polymorphs into a Humanoid or beast that has a Challenge rating equal to or less than its own, or back into its true form. It reverts to its true form if it dies. Any Equipment it is wearing or carrying is absorbed or borne by the new form (the deva's choice).
In a new form, the deva retains its game Statistics and ability to speak, but its AC, Movement modes, Strength, Dexterity, and Special Senses are replaced by those of the new form, and it gains any Statistics and capabilities (except Class Features, legendary Actions, and lair actions) that the new form has but that it lacks.

If the deva changes shape into a brown bear, do its attacks deal extra radiant damage from the Angelic Weapons feature?

We are playing Curse of Strahd and we encounter this creature: a Deva.

It has the Angelic Weapons feature:

The deva's weapon attacks are magical. When the deva hits with any weapon, the weapon deals an extra 4d8 radiant damage (included in the attack).

It also has Change Shape as one of its actions:

The deva magically polymorphs into a Humanoid or beast that has a Challenge rating equal to or less than its own, or back into its true form. It reverts to its true form if it dies. Any Equipment it is wearing or carrying is absorbed or borne by the new form (the deva's choice).
In a new form, the deva retains its game Statistics and ability to speak, but its AC, Movement modes, Strength, Dexterity, and Special Senses are replaced by those of the new form, and it gains any Statistics and capabilities (except Class Features, legendary Actions, and lair actions) that the new form has but that it lacks.

If the deva changes shape into a brown bear, do its attacks deal extra radiant damage from the Angelic Weapons feature?

We are playing Curse of Strahd and we encounter this creature: deva.

It has Angelic Weapons feature:

The deva's weapon attacks are magical. When the deva hits with any weapon, the weapon deals an extra 4d8 radiant damage (included in the attack).

It also has Change Shape in one of its action:

The deva magically polymorphs into a Humanoid or beast that has a Challenge rating equal to or less than its own, or back into its true form. It reverts to its true form if it dies. Any Equipment it is wearing or carrying is absorbed or borne by the new form (the deva's choice).
In a new form, the deva retains its game Statistics and ability to speak, but its AC, Movement modes, Strength, Dexterity, and Special Senses are replaced by those of the new form, and it gains any Statistics and capabilities (except Class Features, legendary Actions, and lair actions) that the new form has but that it lacks.

If the deva change shape into a brown bear, do its attacks deal extra radiant damage from Angelic Weapons feature?

We are playing Curse of Strahd and we encounter this creature: deva.

It has an Angelic Weapons feature:

The deva's weapon attacks are magical. When the deva hits with any weapon, the weapon deals an extra 4d8 radiant damage (included in the attack).

It also has Change Shape in one of its actions:

The deva magically polymorphs into a Humanoid or beast that has a Challenge rating equal to or less than its own, or back into its true form. It reverts to its true form if it dies. Any Equipment it is wearing or carrying is absorbed or borne by the new form (the deva's choice).
In a new form, the deva retains its game Statistics and ability to speak, but its AC, Movement modes, Strength, Dexterity, and Special Senses are replaced by those of the new form, and it gains any Statistics and capabilities (except Class Features, legendary Actions, and lair actions) that the new form has but that it lacks.

If the deva changes shape into a brown bear, do its attacks deal extra radiant damage from the Angelic Weapons feature?