Were planned release dates skipped in 2020 for the VFR sectional charts for Juneau Alaska and Dutch Harbor Alaska?
The FAA has just switched to a 56-day release cycle (double AIRAC cycle) for all VFR sectional charts. In the process of aligning the release cycle, they may have skipped an update. However, the chart of Dutch Harbor was on a cycle of one year before, and would have been due on 25th of February anyway. Juneau was also on a one-year schedule and would have been due on the 25th of March. It is very unlikely that a release would have been skipped.
The story behind the switch to the 56-day release schedule can be found in this FAA briefing. See Milestone #2 below, which may be the reason for skipping a release.

Background/Discussion: The lifecycles of FAA-produced Visual Flight
Rules (VFR) Charts vary from 168 days to two years and at one time
various charts did not update for years longer (Helicopter and Grand
Canyon for example).
Extended and unsynchronized lifecycles create an
undue burden on the NAS and on chart users. The NOTAM System must
carry many facility NOTAMs until consistently charted. As a result,
chart users are burdened with numerous NOTAMS and difficulty arises in
identifying pertinent NOTAMs and correctly applying them. Numerous
changes are alerted in Chart Supplement Chart Bulletins that many
users either do not know exist and/or do not find readily accessible.
Unsynchronized chart dates lead to inconsistent data capture on
overlapping areas, adjacent charts and other chart products.
Producing
56-day VFR Charts will provide significant relief to a number of these
issues. The NAS picture will be consistent with that reflected on
Enroute, Terminal and Supplemental products. NOTAMs will be
significantly reduced as charts will capture changes with every 56-
day AIRAC cycle. Chart Supplement Chart Bulletins will no longer be
necessary.
Planned Actions: Update the VFR Sectional, Terminal Area,
Flyway Planning and Helicopter Route Chart series on the 56-day AIRAC
cycle. Implement this effort across a series of milestones:
Milestone
#1 will synchronize the cutoff for VFR Charts with other aeronautical products. (June 18, 2020)
Milestone #2 will eliminate 28-Day AIRAC
date VFR Charts to align with airspace amendments and will stage
charts for 56-day AIRAC date production. (September 10, 2020)
Milestone #3 will realize full implementation of the 56-day update of
VFR Charts and elimination of supporting Chart Supplement Chart
Bulletins. (February 25, 2021)

And more history can be found here: VFR Chart Print Schedule Realignment and Synchronization