1. Changes in voice actors. Spongebob's original voice actor may leave his job for some reason or cannot continue to participate in animation production, and the new voice actor may not be able to completely restore the original voice characteristics, resulting in a different voice.
2. The problem of dubbing skills. The new voice actor may not be skilled enough to meet the expectations of the audience and his voice may sound unnatural.
3. The quality of film production. Film producers may use low-quality audio equipment or improper post-processing, which will also affect the sound quality and effect of dubbing.
4. The audience's acceptance. The audience has different expectations for the early spongebob voice, which will also make the voice of the new dubbing different from the original.
To sum up, the reasons for the ugliness of Spongebob dubbing may be varied, involving the change of dubbing personnel, dubbing skills, film production quality, audience acceptance and so on.