SuMo bot fails to translate if a prior translation exists

[emilghittasv]

Describe the bug
Access to attributes is not allowed in templates. Attempted to access 'source_text' on dict. Use only simple variable names like {{variable}} without dots or methods.

https://mozilla.sentry.io/issues/7239733290/?project=4504326799753216&query=is%3Aunresolved&referrer=issue-stream

This is happening in both stage and prod

[escattone]

I had claude do some research, and this was caused when we started using langchain-core version 0.3.80+.

The change was introduced in two patch versions, published on November 19, 2025:

• langchain-core 0.3.80 (for the 0.3.x line)
• langchain-core 1.0.7 (for the 1.0.x line)

It was a security fix for GHSA-6qv9-48xg-fc7f — a
template injection vulnerability where attribute access (.) and indexing ([]) in prompt templates could be
exploited to traverse object internals (e.g., globals) and leak sensitive data like environment variables.

The fix enforces that template variable names must be valid Python identifiers, rejecting syntax like {obj.attr},
{obj[0]}, or {obj.class}. Mustache and Jinja2 templates also received defensive hardening.

Sources:

• GHSA-6qv9-48xg-fc7f
• https://docs.langchain.com/oss/python/releases/changelog