文件第二次下载会删除之前下载好的文件，这是为什么

文件第二次下载会删除之前下载好的文件，这是为什么
2023-09-17 10:17:10.812 10048-10048 MultiDownload com.mssm.demoversion D pending taskId:-270459960,fileName:null,soFarBytes:0,totalBytes:0,percent:NaN
2023-09-17 10:17:11.241 10048-10252 MultiDownload com.mssm.demoversion D blockComplete taskId:-270459960,filePath:/storage/emulated/0/MSSMDownload,fileName:20230916_fb4b4fee131a4538a2d52d08f0a0757a.jpg,speed:0,isReuse:true
2023-09-17 10:17:11.251 10048-10252 MultiDownload com.mssm.demoversion D blockComplete: mTaskCount = 1
2023-09-17 10:17:11.282 10048-10048 MultiDownload com.mssm.demoversion D pending taskId:-270459960,fileName:null,soFarBytes:0,totalBytes:0,percent:NaN
2023-09-17 10:17:11.365 10048-10255 MultiDownload com.mssm.demoversion D blockComplete taskId:-270459960,filePath:/storage/emulated/0/MSSMDownload,fileName:20230916_fb4b4fee131a4538a2d52d08f0a0757a.jpg,speed:0,isReuse:true
2023-09-17 10:17:11.381 10048-10255 MultiDownload com.mssm.demoversion D blockComplete: mTaskCount = 0
2023-09-17 10:17:11.391 10048-10255 MultiDownload com.mssm.demoversion D completed

然后第二次20230916_fb4b4fee131a4538a2d52d08f0a0757a.jpg这个文件就被删除了
这是为什么，应该怎么解决

Start by reproducing the second download using the MultiDownload flow and compare the logged taskId, filePath, fileName, and isReuse values across both attempts. Trace the repeated-download handling until the existing file is removed, then verify that completing the second download preserves the first file.

Written by the indexing model from the issue text.