Iteration in Python throws results no desired

I am trying to assign payments which are stored in p vector to the vector of debts which is l, so I need to store the dates of payment and the payed value for each date of payment, according the debts.

This code is for the payments for only the first debt ($254.000) (the position 0 in l):[62998, datetime.date(2019, 11, 29), 254000.0]

The desired results are:

1. fechas_rec=[datetime.date(2020, 1, 30), datetime.date(2020, 2, 28)] vector of payment dates
2. p=[[10000.0, datetime.date(2020, 2, 28)], [110000.0, datetime.date(2020, 3, 30)]] update the payments with the amounts available.
3. recuperados=[137500.0,116500.0] vector of payments according to the vector of the point 1.

But, when update the second last line "recuperados.append()" with the commented code "recuperados.append(‘a’)", the output of the first point change, the question is why?

The new output is:

fechas_rec=[datetime.date(2020, 2, 28), datetime.date(2020, 3, 30)]

Code:

l = [
    [62998, datetime.date(2019, 11, 29), 254000.0],
    [65317, datetime.date(2019, 12, 30), 229000.0],
    [66606, datetime.date(2020, 1, 31), 229000.0],
    [68751, datetime.date(2020, 2, 28), 228000.0],
    [70652, datetime.date(2020, 3, 24), 229000.0],
]

p = [
    [137500.0, datetime.date(2020, 1, 30)],
    [126500.0, datetime.date(2020, 2, 28)],
    [110000.0, datetime.date(2020, 3, 30)],
]


for j in l:
    fechas_rec = []
    recuperados = []
    suma = 0
    for i in enumerate(p):
        suma = suma + i[1][0]
        if suma <= j[2]:
            fechas_rec.append(i[1][1])
            recuperados.append(i[1][0])
        else:
            val = suma - j[2]
            c = i[1]
            del p[: i[0] + 1]
            p.insert(0, [val, c[1]])
            fechas_rec.append(i[1][1])
            recuperados.append()  # recuperados.append('a')
            break

l = [
    [62998, datetime.date(2019, 11, 29), 254000.0],
    [65317, datetime.date(2019, 12, 30), 229000.0],
    [66606, datetime.date(2020, 1, 31), 229000.0],
    [68751, datetime.date(2020, 2, 28), 228000.0],
    [70652, datetime.date(2020, 3, 24), 229000.0],
]

p = [
    [137500.0, datetime.date(2020, 1, 30)],
    [126500.0, datetime.date(2020, 2, 28)],
    [110000.0, datetime.date(2020, 3, 30)],
]

for j in l:
    fechas_rec=[]
    recuperados=[]
    suma=0
    for i in enumerate(p):
        suma1=suma
        suma=suma+i[1][0]
        if suma<=j[2]:
            fechas_rec.append(i[1][1])
            recuperados.append(i[1][0])
        else:
            val=suma-j[2]
            c=i[1]
            del p[:i[0]+1]
            p.insert(0,[val,c[1]])
            fechas_rec.append(i[1][1])
            recuperados.append(j[2]-suma1) 
            break  
    drec.append([j[0],fechas_rec,recuperados])    
    sumtot=sumtot+sum(drec[-1][2])
    if sumtot==rectot:
        test=True       
    if test:
        break