I suspect there is a larger issue here that apple has not made public.
I see multiple processes related to server based tasks spinning out of control on all of my Apple devices connected to my iCloud account, and appear to impact other accounts associated with my account through Family Sharing, thought I can't say if this is an issue with Family Sharing OR a result of sharing a large volume of Notes, Calendars, etc with another Apple ID.
At this point I have Apple watches I can't use because they fill with log data and I experience a wide variety of odd behaviors I've never noticed in the years of advanced user experience with my apple products.
The issues I've had were so severe and atypical that I felt compelled to report them to the authorities, documenting what I witnessed in the event this becomes a larger issue related to apples platform security.
Apple is being very quiet, they have no timeline for addressing our Watches, their front line support is not informed on the issue, and I continue to see a large volume of data being transferred between Apple processes and I what I hope are their servers, I'm not able to tell because Apple has masked all relevant console data with 'Private'.
Today I work from my Laptop and iPhone primarily with my desktop devices and watches offline and in storage. At the moment I see the 'routined' process using 103% of CPU resources with 13:30:10 hours on the CPU Time.
This is typical behavior I've noticed since April/May. An apple process that appears related to syncing with iCloud or managing communications has a process that runs away, using massive amount of resources for no apparent reason as my iCloud activity to my knowledge, based on how I use my machine does not appear to indicated this demand.
Since may I've taken steps to isolate my machine as best I can, going so far as to securely wipe and network restore all of our iOS devices only to find the behavior return once they are associated with our Apple IDs and iCloud services.
I've mentioned this connection to front line support and provided apple with sysDiag logs across all of my devices to document the behaviors, going so far as to capture console messages, logs, and other images during the event.
I've opened ~10 feedback tickets since April outlining the odd behaviors and system performance issues I've faced. Apple's response? Silence.
I work in healthcare, I have access to sensitive data, many of these behaviors appeared more dramatically (OS crashes) soon after signing a contract to provide reporting support for a government agency.
Because of my background I pay very close attention to how my devices function and I've installed all of the typical and more advanced tools to ensure my machine remains clear from outside influence, I don't open email attachments and proactively report emails to iCloud Spam or other providers when they come across.
I'm not sure how many others are out there in similar situations, I've seen over a hundred views on my community threads related to my Apple Watch issues, with a few people reporting similar behavior, all hearing the same response from apple... TBD.
At this point all I can do is document, my devices continue to be unstable, requiring reboots to resolve issues with bluetooth connectivity, app unresponsiveness, and memory use. Again, none of these responses to demand by my devices align with my actual usage of the device.
Any who, that's my experience so far. I hope this will help others.
Jason