Re: [CC and Milestones, error code 110-578ef827] Stuck On Loading Screen Sims 4

With the recent version of TS4, I began getting an infinite loading screen error and/or an inability to play households and being automatically spit back out to the choose world screen. So I did the following:

1) updated all my mods
2) removed all my mods and tried to figure out which ones were causing the issue. I did have several mods that were causing other issues and have removed them from my game.
3) batch updated my cc
4) repaired my game without mods
5) checked my last exception files without mods

Now my game has no mods, has been repaired several times, and has generated the same last exception report several times and given me the same error code each time. I cannot figure out what the error code is for and I don't understand how to address the issues in my last exception files.

After much testing, I have discovered that I cannot play any households with babies, infants, or toddlers. I can visit households that have this age of sims but I cannot play families with these ages of sims. If I try to add one of these sims to my household, the next time I load onto a lot, I am hit with an infinite loading screen or spat back to the world select screen with an error code. Houses with young adults, adults, elders, and pets play just fine.

The error code is 110:326b75c1:c52bd682

The last exception file is this: 
<?xml version="1.0" ?><root>
<report><version>2</version><sessionid>36c58d25c75a503368a66a2d</sessionid><type>desync</type><sku>ea.maxis.sims4_64.15.pc</sku><createtime>2025-08-20 20:38:31</createtime><buildsignature>Local.Unknown.Unknown.1.117.227.1030-1.200.000.673.Release</buildsignature><categoryid>developmental_milestone_tracker.py:1114</categoryid><desyncid>36c58d25c75a503368a66a2d</desyncid><systemconfig/><screenshot/><desyncdata>Exception raised while processing zone spin up sequence: 'Object not found: 0x858cd2ee' (KeyError: 'Object not found: 0x858cd2ee')&#13;&#10;Traceback (most recent call last):&#13;&#10;&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\areaserver.py", line 130, in wrapped&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\areaserver.py", line 126, in finally_wrap&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Core\sims4\utils.py", line 157, in wrapper&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Core\sims4\utils.py", line 175, in wrapper&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\areaserver.py", line 383, in c_api_client_connect&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\zone.py", line 612, in do_zone_spin_up&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\zone_spin_up_service.py", line 1757, in update&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\zone_spin_up_service.py", line 846, in on_update&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\zone.py", line 1076, in on_all_sims_spawned&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\zone.py", line 1142, in _set_zone_state&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Core\sims4\callback_utils.py", line 158, in __call__&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\developmental_milestones\developmental_milestone_tracker.py", line 274, in start_milestone_tracker&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\developmental_milestones\developmental_milestone_tracker.py", line 731, in _activate_available_milestones&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\developmental_milestones\developmental_milestone_tracker.py", line 565, in activate_milestone&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\developmental_milestones\developmental_milestone_tracker.py", line 315, in process_evaluation&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\developmental_milestones\developmental_milestone_tracker.py", line 1206, in send_all_milestones_update_to_client&#13;&#10;  File "T:\InGame\Gameplay\Scripts\Server\developmental_milestones\developmental_milestone_tracker.py", line 1114, in _get_milestone_update_msg&#13;&#10;KeyError: 'Object not found: 0x858cd2ee'rtim=0&#13;&#10;Client Session Time: 17.16&#13; &#10;Num Save Errors: 0&#13; &#10;Num Load Errors: 0&#13; &#10;Current Game State: 0x96d01090&#13; &#10;LoadingScreenActiveFlag: 1&#13; &#10;Origin Version: 13,531,2,6045&#13; &#10;Modded: False&#13; &#10;SystemInfo: Windows 10 10.0.19045 GPU: NVIDIA GeForce GTX 1050 Ti  32.0.15.6094, GUID: A5376FE4-7E66-11EC-9375-806E6F6E6963&#13; &#10;</desyncdata></report>
</root>


Please note that I have also tested a brand new save file by importing a family with a baby into the new save and the same error generates for all three early life stages. I have not tried creating a new baby inside a new save yet as it seems rather time consuming without the use of MCCC.

Please advise on solutions that I have not already tried.