From the Tebenkof paper conclusions, and probably why denialists are cherry picking data from conflicting papers on the Glacier:

Tidewater glacier fluctuations are asynchronous with
other termini because of factors such as iceberg-calving and fjord
geometry, and the typically long interval between successive advances
means that logs found in tidewater glacier deposits often have
significantly more rings than those found on terrestrial forefields
where terminus expansions have been more frequent. While these
factors make the histories of tidewater glaciers unsuitable for
interpretation as climate proxies, tree-ring collections from such
glaciers are essential for the development of long tree-ring chronologies
in the southern Alaskan region.