Symptom:
The mandatory SMU must be installed before SP3:

asr9k-px-4.3.4.CSCul58246-1.0.0
asr9k-px-4.3.4.CSCui94441-1.0.0
asr9k-px-4.3.4.CSCug75299-1.0.0

When complete, install SP3.

"show install active" output will not indicate the SMU that was previously installed.

Conditions:
RP/0/RSP0/CPU0:ASR9006-E#show install active summary
Mon Nov 24 15:57:15.250 UTC
Default Profile:
  SDRs:
    Owner
  Active Packages:
    disk0:asr9k-mini-px-4.3.4
    disk0:asr9k-doc-px-4.3.4
    disk0:asr9k-k9sec-px-4.3.4
    disk0:asr9k-mpls-px-4.3.4
    disk0:asr9k-mgbl-px-4.3.4
    disk0:asr9k-mcast-px-4.3.4
    disk0:asr9k-fpd-px-4.3.4
    disk0:asr9k-video-px-4.3.4
    disk0:asr9k-px-4.3.4.sp3-1.0.0

THIS IS WHAT WAS COMMITED:

RP/0/RSP1/CPU0:ASR9006-E(admin)#show install commit summary
Mon Nov 24 16:24:19.401 UTC
Default Profile:
  SDRs:
    Owner
  Committed Packages:
    disk0:asr9k-mini-px-4.3.4
    disk0:asr9k-doc-px-4.3.4
    disk0:asr9k-k9sec-px-4.3.4
    disk0:asr9k-mpls-px-4.3.4
    disk0:asr9k-mgbl-px-4.3.4
    disk0:asr9k-mcast-px-4.3.4
    disk0:asr9k-fpd-px-4.3.4
    disk0:asr9k-video-px-4.3.4
    disk0:asr9k-px-4.3.4.sp3-1.0.0
    disk0:asr9k-px-4.3.4.CSCul58246-1.0.0
    disk0:asr9k-px-4.3.4.CSCug75299-1.0.0
    disk0:asr9k-px-4.3.4.CSCui94441-1.0.0