This might be the answer. It is not that the language became more popular, but rather the search keyword ada...
> This Month's Changes in the Index
> William Herrera told us that programming language ADA might have been boosted in the TIOBE index because of the Ada Lovelace architecture of NVIDIA. For this reason we have added "-NVIDIA" to Ada's search term. As a consequence, Ada dropped from position #9 last month to position #13 this month.
GhosT078 · 2h ago
Well, that will erroneously drop the ranking because NVIDIA themselves use the Ada programming language. Refer to:
> This Month's Changes in the Index > William Herrera told us that programming language ADA might have been boosted in the TIOBE index because of the Ada Lovelace architecture of NVIDIA. For this reason we have added "-NVIDIA" to Ada's search term. As a consequence, Ada dropped from position #9 last month to position #13 this month.
https://nvidia.github.io/spark-process/
https://www.nvidia.com/en-us/on-demand/session/gtcsj20-s2112...
The term "Ada" appears in several contexts (sometimes for the same company) so keyword filters should not be used in such a simpleminded way.