Hi John,
How has the water level been? S.flava does most of it's
trapping in the spring/early summer. Some plants follow this
and some don't seem to care too much. Most of my S.flava will
grow somewhat bent and floppy (frail) pitchers in later summer
and growing good a pitcher only rarely this time of year. I
don't really get phyllodia (leaves w/out pitchers) until the
very end of the season but those floppy traps which are somewhat
in between the pitcher and phyllodia. This is probably what
your's are doing, since they have been growing for several
months already.
Where are you located? There are insects which can borrow
into the rhizome and eat it in the southeast part of the US.
This would most certainly effect the growth also.
Dave Evans