Having multiple clients open leads to storm of identical /v3/sync responses #2047

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opened 2026-07-26 13:07:21 +00:00 by theta · 2 comments

theta commented

2026-07-26 13:07:21 +00:00

Having multiple clients open results in all of them receiving a barrage of instant /v3/sync responses, carrying either identical-to-previous or empty fields (usually device_unused_fallback_key_types and device_one_time_keys_count). The specific contents received depend on the client pair currently open, but they are always completely identical and come down rapidly (up to 5 per second).

Example sync responses coming down to Element Web and Element Classic (mobile) pair:

{
  "next_batch": ...,
  "device_one_time_keys_count":{"signed_curve25519":50},
  "device_unused_fallback_key_types":["signed_curve25519"]
}

These come down about twice per second with the exact same content (only next_batch is different).

Having multiple clients open results in all of them receiving a barrage of instant /v3/sync responses, carrying either identical-to-previous or empty fields (usually `device_unused_fallback_key_types` and `device_one_time_keys_count`). The specific contents received depend on the client pair currently open, but they are always completely identical and come down rapidly (up to 5 per second). Example sync responses coming down to Element Web and Element Classic (mobile) pair: ```json { "next_batch": ..., "device_one_time_keys_count":{"signed_curve25519":50}, "device_unused_fallback_key_types":["signed_curve25519"] } ``` These come down about twice per second with the exact same content (only next_batch is different).