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It seems that revision 0xe2 fixes[1][2] system instability issues observed with revision 0xdc[3].

[1] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/31#issuecomment-726760336
[2] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/38#issuecomment-725398419
[3] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/31#issuecomment-644885826

microcode-20210608 comes with a new revision 0xea of 06-4e-03/06-5e-03, that seems to solve[1][2] the issue.

[1] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/31#issuecomment-857507126
[2] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/47#issuecomment-857815716

Revision 0xea still hasn't fixed the issue[1], at least for 06-4e-03.  It may be worth enabling 06-5e-03 only, as this is the CPUID that includes some server (Xeon E3 v5) models, contrary to 06-4e-03, that is mobile-only.

[1] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/31#issuecomment-861674762

06-4e-03 continues to have (possibly unrelated) issues[1]; on the other hand, there are no new reports for 06-5e-03, it can't be reproduced in-house, and enabling microcode-provided protections is more pertinent for it, thus, the bug is re-scoped to include 06-5e-03 only.

[1] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/31#issuecomment-861674762

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Important: microcode_ctl security, bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2021:3028