Sadly this is something that are hard to implement by PKBSI towards their members. These facilities have considerable voices within the organization and PKBSI itself aren't always particularly strict when enforcing rules, which is how we got zoos like Lembang Park & Zoo.
Likely causes are how "cheaper" getting and taking care of farm-bred tigers are compared to Sumatran tigers, especially for commercial zoos like Lembang and barely conservationaly competent zoos like Bandung and Surabaya (Who also trying to move towards acquiring exotic cats). Additionaly, these zoos, due to their nature, are of course trying to minimize administrative and bureaucratic works regarding native critical species husbandry while focusing mostly on capital profit and social engagement. Which explain how Lembang have made no effort in even getting a partner for most of their native endangered mammals (Let alone have any actual breeding project) and instead focusing on importing popular exotic animals (Even then they came from private farms/suppliers, as Lembang has reportedly bad papers on their husbandry of larger mammals).