The fix in JCE Pro 2.9.27 is not related to SP Page Builder, as SP Page Builder does not use the method affected.
Also, in testing this for a user, SP PageBuilder PRO 3.8.7 also does not work with JCE Pro 2.9.24, which did not have the bug fixed in JCE Pro 2.9.27
I am not seeing any issue with saving in SP PageBuilder Lite 3.8.7
I've just tested with SP PageBuilder PRO 3.8.6 and I'm not seeing any issue with saving with JCE Pro.
The bug appears to be in SP PageBuilder PRO 3.8.7...
Thanks
Ryan
JCE Developer