"If I select another track it import track 1 the bass track.."

That's because it would be the same text file that was originally created with the earlier version because you don't have the Track menu in 426 now to write the temp/trackdata to a new text file.

You will see in the video the text files being created, read then closed
Video Text Files

This it what Biab RB and BiabVST need to do to give incredibly quick generate and play times rather than writing all the sections into RAM then rendering that down to a consolidated wav file that you can't tweak and change sections in.
Reaper will play these while Biab is still writing them into RAM let alone render down to wav.

trackdata.txt for midi file
Code:
Paste into a spreadsheet. List of Events in the track=	141
Status	Channel	Stamp	Bar	Beat	Tick120	NoteNum	Name	Vel	Duration	
NoteOn	3	1080	1	2	0	69	A 5	84	240	
NoteOn	3	1320	1	4	0	69	A 5	84	60	
NoteOn	3	1380	1	4	60	72	C 6	84	60	
NoteOn	3	1440	2	1	0	71	B 5	84	360	
NoteOn	3	1800	2	4	0	71	B 5	84	120	
NoteOn	3	1920	3	1	0	70	Bb 5	84	420	
NoteOn	3	2340	3	4	60	72	C 6	84	60

temp.txt for realtrack
Code:
Riff #	Summary	RiffHasData	SourceWAVFileName	SourceWAVFileTempo	SourceBarNumber	SourceBeatNumber	SourceTimeSig	SourceStartTimePPQ1200	*SourceBar	*SourceTick(120)	SourceTickOffsetPPQ1200	SourceEndTimePPQ1200	*Tick Duration120(calc)	*Beats Duration (calc)	SourceEndRiffStretchAmountPPQ1200	SourceEndRiffTransitionAmountPPQ1200	DestinationStartTimePPQ1200	*Chord	*Bar Destination 	*Beat Destination 	*Tick Destination120 	TranspositionSemitonesRequired	ThisRiffIsaPush1200	ThisRiffNumber	RiffNoneHoldShot	RiffHoldsLibraryNumber	ThisIsaPush	ThisisDrums	RiffdbOffset	RiffSoloistNumber	RiffThisRiffStartShouldBeMergedWithEndOfPreviousOne	RiffIsUnknownMonoStereo	RiffIndexFromMultipleRT	RiffMultipleRealTracksNumber	AnyLoopActive	AnyLoopRestartLoopWhenWavEnds	AnyLoopBaseTempo	AnyLoopNumberOfBeats	AnyLoopTransposeAmount	AnyLoopStretchTempo	AnyLoopTranspose	AnyLoopOriginalKeyMod	ChordLoopActive	ForceUsePlusMinusRealtracks	RiffPanning	RiffInstructionFutureBytes
0	Riff 1:1:116 to 3:4:41, dur=1246, beats=10, ticks=+46,leadin120=116	1	D:\bb\RealTracks\Flugelhorn, Background BossaPads Ev 110 (1TrackHornSection)\tp1019.WAV	110	1	1	4	10768	1	116	0	23232	1246	10.39	0	0	10768		1	1	117	0	0	12835	0	0	0	0	0	3448	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	
1	Riff 3:4:51 to 5:4:45, dur=955, beats=7, ticks=+115,leadin120=-69	1	D:\bb\RealTracks\Flugelhorn, Background BossaPads Ev 110 (1TrackHornSection)\tp1004.WAV	110	30	1	4	148115	29	411	0	157667	955	7.96	0	0	23315		3	4	52	0	0	3450	0	0	0	0	0	3448	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	
2	Riff 5:4:60 to 7:1:81, dur=622, beats=5, ticks=+22,leadin120=-60	1	D:\bb\RealTracks\Flugelhorn, Background BossaPads Ev 110 (1TrackHornSection)\tpt998.WAV	110	51	1	4	249000	50	420	0	255229	623	5.19	0	0	33000	Fdim	5	4	60	0	0	20015	0	0	0	0	0	3448	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	
3	Riff 7:1:116 to 7:4:107, dur=352, beats=2, ticks=+112,leadin120=116	1	D:\bb\RealTracks\Flugelhorn, Background BossaPads Ev 110 (1TrackHornSection)\TP1013-1.WAV	110	42	1	4	207563	42	116	0	211083	352	2.93	0	0	39563	C7	7	1	116	0	0	10005	0	0	0	0	0	3448	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	
4	Riff 7:4:49 to 8:4:92, dur=524, beats=4, ticks=+44,leadin120=-71	1	D:\bb\RealTracks\Flugelhorn, Background BossaPads Ev 110 (1TrackHornSection)\tp1014.WAV	110	4	1	4	23293	3	409	0	28541	525	4.37	0	0	42493		7	4	49	0	0	10904	0	0	0	0	0	3448	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	
5	Riff 8:4:117 to 11:4:103, dur=1427, beats=11, ticks=+107,leadin120=-3	1	D:\bb\RealTracks\Flugelhorn, Background BossaPads Ev 110 (1TrackHornSection)\TPT998+2.WAV	110	15	1	4	76773	14	477	0	91051	1428	11.90	0	0	47973	Dm7	8	4	117	0	0	19361	0	0	0	0	0	3448	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	
6	Riff 11:4:50 to 12:4:95, dur=526, beats=4, ticks=+46,leadin120=-70	1	D:\bb\RealTracks\Flugelhorn, Background BossaPads Ev 110 (1TrackHornSection)\tp1016.WAV	110	26	1	4	128905	25	410	0	134171	527	4.39	0	0	61705		11	4	50	0	0	12207	0	0	0	0	0	3448	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	
7	Riff 13:1:0 to 13:4:106, dur=467, beats=3, ticks=+107,leadin120=0	1	D:\bb\RealTracks\Flugelhorn, Background BossaPads Ev 110 (1TrackHornSection)\TP1007-2.WAV	110	1	1	4	9606	1	0	0	14285	468	3.90	0	0	67206	Am7b5	13	1	1	0	0	5468	0	0	0	0	0	3448	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

https://stash.reaper.fm/u/ReaTrak (Scripts for Biab Reaper)
Open SGU in Reaper Instantly