pipelinedb: pg_stat_statements incompatibility

I am in the process of migrating a lot of data from 0.9.7 to 0.9.8 and have discovered that combine no longer works.

CREATE STREAM s (n int);

CREATE CONTINUOUS VIEW cv AS
  SELECT avg(n)
  FROM s;

SELECT combine(avg) FROM cv;

results in the following error:

ERROR:  the FROM clause is not a continuous view
HINT:  Only aggregate continuous view columns can be combined.

PipelineDB 0.9.8 at revision d1c40b1bda8de58ae27cca84acc15478e8c4147f on x86_64-pc-linux-gnu, compiled by gcc (Debian 6.3.0-18) 6.3.0 20170516, 64-bit

Am I missing something obvious? I didn’t see any notes about this in the 0.9.8 release blog, but it seems like something this big would have been caught by CI tests.