August 4, 2018, which includes the points:
"...the United States, is willing to assist in building submarines [for Taiwan]. Indeed, in April 2018 the State Department approved a marketing license for submarine parts to Taiwan, including a Combat Management System. Taiwan already possesses licenses for Mark 48 torpedoes and Harpoon missiles." but
"European countries are wary of inciting Beijing’s wrath, though the Dutch RH Marine [see ISM article] did recently agree to overhaul Taiwan’s Zwaardvis[/Hai Lung]-class submarines in 2022".
Yes US, European and Asian companies are pretty reticent about publicising that they have helped or will help Taiwan. Since April 4 I've located an additional company that already has an export license to help Taiwan on submarines, hence can help the future submarine project.
This DefenseNews article of April 4, 2016 indicates:
"... Taiwan Navy sources say that Navy leadership are leaning towards an off-the-shelf solution, such as that being proposed by Lockheed Martin based on its SUBICS (SUBmarine Integrated Combat System) system, instead of an indigenous combat system solution to be developed by CSIST, presumably with foreign technical assistance."
[And the following is pretty definitive for the 2016 AND most probably also the future Taiwanese submarine project]
"US Government sources confirm that Lockheed Martin had received the export license earlier in  to assist Taiwan in submarine combat system and other submarine-related work."