[ISSUE] utils.ts?61cd:83 Uncaught (in promise) M_MISSING_PARAM: MatrixError: [400] 1 validation error for PutBody device_id field required

[menturion]

synapse: v1.70.0
matrix-js-sdk: v21.0.0

After I updated to Synapse v1.70.0 I get the below issue shown in the console:

fetch.ts?12e2:62 PUT /_matrix/client/unstable/org.matrix.msc2697.v2/dehydrated_device 400 (Bad Request)
utils.ts?61cd:83 Uncaught (in promise) M_MISSING_PARAM: MatrixError: [400] 1 validation error for PutBody device_id field required (type=value_error.missing) (/_matrix/client/unstable/org.matrix.msc2697.v2/dehydrated_device)
    at parseErrorResponse (webpack-internal:///319:89:12)
    at MatrixHttpApi.requestOtherUrl (webpack-internal:///315:289:78)

... and the following error msg in homeserver.log:

2022-10-26 14:16:56,492 - synapse.http.server - 108 - INFO - PUT-625 - <SynapseRequest at 0x7fd1fef34100 method='PUT' uri='/_matrix/client/unstable/org.matrix.msc2697.v2/dehydrated_device' clientproto='HTTP/1.1' site='8448'> SynapseError: 400 - 1 validation error for PutBody device_id field required (type=value_error.missing)

[t3chguy]

This looks like a bug in Synapse, the MSC doesn't say anything about a request param of device_id for the PUT request.
https://github.com/uhoreg/matrix-doc/blob/dehydration/proposals/2697-device-dehydration.md#dehydrating-a-device

Tracked in matrix-org/synapse#14334

[menturion]

Many thanks!