UPDATE: Support reviewed our logs and provided the following response (although I'm not sure if it was a result of something they found in the logs, which I have asked):
"There is an ongoing investigation by our development team regarding a known issue with a new experimental feature released by Chrome that is affecting any CRM client: Storage Partitioning - Chrome Developers
We ask that all affected customers explicitly disable this setting to prevent the behavior while we investigate the long term solution on our side.
This can be disabled by navigating directly to chrome://flags/#third-party-storage-partitioning in the browser and explicitly setting this configuration to Disabled. There are also a couple of ways to manage this at an enterprise level so that all users do not need to set this flag individually:
https://chromeenterprise.google/policies/#ThirdPartyStoragePartitioningBlockedForOrigins
https://chromeenterprise.google/policies/#DefaultThirdPartyStoragePartitioningSetting
It appears that this setting is also present in other Chromium based browsers such as Edge and Brave, the flag location is identical other than the browser name specification so can be found at these locations:
edge://flags/#third-party-storage-partitioning
brave://flags/#third-party-storage-partitioning
As some have noted these browsers are not yet experiencing this issue as it appears they've not yet updated the default setting for it to be enabled, however the suggestion for the time being would still be to disable the setting so that a version update in the near future does not change that and begin causing the same issue with our client.