Issue on GRANT query

I'm having trouble running grant queries.

The variables are:
tableArray = ['schema.table1','schema.table2']
roleName = 'example'

This query works fine:
GRANT INSERT ON ${this.sql(tableArray)} TO ${this.sql(roleName)}

the generated query is correct:
GRANT SELECT ON "schema"."table1","schema"."table2" TO "example"

This one doesn't work:
GRANT UPDATE ON ${this.sql(tableArray)} TO ${this.sql(roleName)}

the generated query is invalid:
GRANT UPDATE ON "0"=$1,"1"=$2 TO "example"

Is this a bug in the system that understands what to replace in the query?

Start by tracing the sql interpolation behavior for tableArray in the postgres.js query builder, comparing the generated GRANT INSERT and GRANT UPDATE statements shown in the report. Reproduce the example with the two table names and role, then confirm that the UPDATE form generates valid PostgreSQL GRANT SQL rather than the "0"=$1,"1"=$2 output.